diff --git a/CMakeLists.txt b/CMakeLists.txt
index 05ea693817304568a6727e7d802382a721614139..11ccb223031131b585ae4f45d61cc4bb4d60565c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,9 +22,9 @@ cmake_minimum_required(VERSION 3.13)
 
 set(libcaosdb_VERSION 0.1.0)
 set(libcaosdb_COMPATIBLE_SERVER_VERSION_MAJOR 0)
-set(libcaosdb_COMPATIBLE_SERVER_VERSION_MINOR 5)
+set(libcaosdb_COMPATIBLE_SERVER_VERSION_MINOR 6)
 set(libcaosdb_COMPATIBLE_SERVER_VERSION_PATCH 0)
-set(libcaosdb_COMPATIBLE_SERVER_VERSION_PRE_RELEASE "GRPC${libcaosdb_VERSION}")
+set(libcaosdb_COMPATIBLE_SERVER_VERSION_PRE_RELEASE "")
 
 project(libcaosdb
     VERSION ${libcaosdb_VERSION}
@@ -162,6 +162,9 @@ if("${CMAKE_BUILD_TYPE}" MATCHES "Debug")
 
         $<INSTALL_INTERFACE:include>
     )
+    target_include_directories(caosdb_grpc SYSTEM PUBLIC
+        ${CONAN_INCLUDE_DIRS}
+    )
 else()
     add_library(caosdb
         SHARED ${libcaosdb_INCL} ${libcaosdb_SRC} ${GRPC_GENERATED})
@@ -178,12 +181,24 @@ target_include_directories(caosdb PUBLIC
     $<BUILD_INTERFACE:${libcaosdb_BINARY_DIR}/include>
     $<INSTALL_INTERFACE:include>
 )
+target_include_directories(caosdb SYSTEM PUBLIC
+    ${CONAN_INCLUDE_DIRS}
+)
 
 add_library(ccaosdb SHARED src/ccaosdb.cpp)
 target_link_libraries(ccaosdb
-    ${LIBCAOSDB}
     ${CONAN_LIBS}
+    ${LIBCAOSDB}
+)
+target_include_directories(ccaosdb PUBLIC
+    $<BUILD_INTERFACE:${libcaosdb_SOURCE_DIR}/include>
+    $<BUILD_INTERFACE:${libcaosdb_BINARY_DIR}/include>
+    $<INSTALL_INTERFACE:include>
 )
+target_include_directories(ccaosdb SYSTEM PUBLIC
+    ${CONAN_INCLUDE_DIRS}
+)
+
 
 add_executable(ccaosdbcli EXCLUDE_FROM_ALL src/ccaosdbcli.c)
 target_include_directories(ccaosdbcli SYSTEM PUBLIC
@@ -194,9 +209,14 @@ target_include_directories(ccaosdbcli PUBLIC
     $<BUILD_INTERFACE:${libcaosdb_BINARY_DIR}/include>
     $<INSTALL_INTERFACE:include>
 )
+target_include_directories(ccaosdbcli SYSTEM PUBLIC
+    ${CONAN_INCLUDE_DIRS}
+)
+
 target_link_libraries(ccaosdbcli
-    ccaosdb
     ${CONAN_LIBS}
+    ${LIBCAOSDB}
+    ccaosdb
 )
 
 add_executable(cxxcaosdbcli EXCLUDE_FROM_ALL src/cxxcaosdbcli.cpp)
@@ -208,6 +228,9 @@ target_include_directories(cxxcaosdbcli PUBLIC
     $<BUILD_INTERFACE:${libcaosdb_BINARY_DIR}/include>
     $<INSTALL_INTERFACE:include>
 )
+target_include_directories(cxxcaosdbcli SYSTEM PUBLIC
+    ${CONAN_INCLUDE_DIRS}
+)
 target_link_libraries(cxxcaosdbcli
     ${LIBCAOSDB}
     ${CONAN_LIBS}
diff --git a/conanfile.py b/conanfile.py
index 78425df0cf78e7b5d78344898b887a75c756429d..6fc869fb02b3e5577a5af06c647df1dcf3048958 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -23,7 +23,7 @@ class CaosdbConan(ConanFile):
     exports = ("*.cmake", "*CMakeLists.txt", "*.in",
                "*.h", "*.proto", "*.c", "*.cpp",
                "*.rst", "*.md",
-               )
+              )
     exports_sources = "src", "doc", "include", "test", "cmake", "proto"
 
     def config_options(self):
diff --git a/doc/README_SETUP.md b/doc/README_SETUP.md
index 0c81e17bba384dbd3274ee5d357b07adf2d5e64c..ceb857617f4c4a890a15afa65a7a58e7db857e76 100644
--- a/doc/README_SETUP.md
+++ b/doc/README_SETUP.md
@@ -102,7 +102,7 @@ The client will load the configuration file from the first existing
 file in the following locations (precedence from highest to lowest):
 
 1. A file specified by the environment variable
-   `$CAOSDB_CLIENT_CONFIGURATION`.
+`$CAOSDB_CLIENT_CONFIGURATION`.
 2. `$PWD/caosdb_client.json`
 3. `$PWD/caosdb-client.json`
 4. `$PWD/.caosdb_client.json`
@@ -124,10 +124,10 @@ For the tests there is a slightly different setup required (with option `-D CMAK
 2. `conan install .. ` (with gcc, append ` -s "compiler.libcxx=libstdc++11"`, with apple-clang,
    append ` -s compiler.cppstd=17`)
 3. `cmake -B . -D CMAKE_BUILD_TYPE=Debug ..`
-   * If your clang-format version is too old, formatting, linting etc. can be skipped:
-	 `cmake -B . -D CMAKE_BUILD_TYPE=Debug -D SKIP_LINTING=ON ..`
-   * Depending on the clang version it might be necessary to also add
-	 `-DCMAKE_CXX_FLAGS="-Wno-unused-parameter"`
+* If your clang-format version is too old, formatting, linting etc. can be skipped:
+ `cmake -B . -D CMAKE_BUILD_TYPE=Debug -D SKIP_LINTING=ON ..`
+* Depending on the clang version it might be necessary to also add
+ `-DCMAKE_CXX_FLAGS="-Wno-unused-parameter"`
 5. `cmake --build .`
 
 #### Run ####
diff --git a/include/caosdb/certificate_provider.h b/include/caosdb/certificate_provider.h
index 197ab7277a8110063351718897b65c8db3289768..1fd4a80b630e53b8b704b29f7803837a3cff6ced 100644
--- a/include/caosdb/certificate_provider.h
+++ b/include/caosdb/certificate_provider.h
@@ -22,10 +22,9 @@
 #ifndef CAOSDB_CERTIFICATE_PROVIDER_H
 #define CAOSDB_CERTIFICATE_PROVIDER_H
 
-#include <boost/filesystem/path.hpp> // for path
-
+#include <filesystem> // for path
 namespace caosdb::configuration {
-using boost::filesystem::path;
+using std::filesystem::path;
 
 class CertificateProvider {
 public:
diff --git a/include/caosdb/configuration.h b/include/caosdb/configuration.h
index 1c3f0148a6679fd152563bd11859d2cab28a9d1a..b360632cf98b8f00d8f19246b09a30b0a98f1e4e 100644
--- a/include/caosdb/configuration.h
+++ b/include/caosdb/configuration.h
@@ -41,8 +41,6 @@
 #include <string> // for string
 
 namespace caosdb::configuration {
-using boost::filesystem::exists;
-using boost::filesystem::path;
 using boost::json::array;
 using boost::json::object;
 using boost::json::value;
@@ -52,6 +50,8 @@ using caosdb::exceptions::ConfigurationError;
 using caosdb::utility::load_json_file;
 using google::protobuf::Arena;
 using grpc::ChannelCredentials;
+using std::filesystem::exists;
+using std::filesystem::path;
 
 const std::string logger_name = "caosdb::configuration";
 
diff --git a/include/caosdb/connection.h b/include/caosdb/connection.h
index c11eaa1d6863f9f256164e0897463ff1afb720ad..238fb1c97331feb26be577ca6f225b1c5b860cea 100644
--- a/include/caosdb/connection.h
+++ b/include/caosdb/connection.h
@@ -27,21 +27,20 @@
  * @date 2021-05-18
  * @brief Configuration and setup of the connection.
  */
-#include "caosdb/authentication.h"               // for Authenticator
-#include "caosdb/configuration.h"                // for ConnectionConfigura...
+#include "caosdb/authentication.h"         // for Authenticator
+#include "caosdb/configuration.h"          // for ConnectionConfigura...
 #include "caosdb/entity/v1/main.grpc.pb.h" // for EntityTransactionSe...
 #include "caosdb/info.h"                         // for VersionInfo
 #include "caosdb/info/v1/main.grpc.pb.h"   // for GeneralInfoService:...
-#include "caosdb/transaction.h"                  // for Transaction
-#include "caosdb/transaction_status.h"           // for TransactionStatus
-#include <boost/filesystem/path.hpp>             // for path
-#include <grpcpp/channel.h>                      // for Channel
-#include <map>                                   // for map
-#include <memory>                                // for shared_ptr, unique_ptr
-#include <string>                                // for string, basic_string
+#include "caosdb/transaction.h"            // for Transaction
+#include "caosdb/transaction_status.h"     // for TransactionStatus
+#include <filesystem>                      // for path
+#include <grpcpp/channel.h>                // for Channel
+#include <map>                             // for map
+#include <memory>                          // for shared_ptr, unique_ptr
+#include <string>                          // for string, basic_string
 
 namespace caosdb::connection {
-using boost::filesystem::path;
 using caosdb::authentication::Authenticator;
 using caosdb::configuration::ConnectionConfiguration;
 using caosdb::entity::v1::EntityTransactionService;
@@ -50,6 +49,7 @@ using caosdb::info::VersionInfo;
 using caosdb::info::v1::GeneralInfoService;
 using caosdb::transaction::Transaction;
 using caosdb::transaction::TransactionStatus;
+using std::filesystem::path;
 
 /**
  * @brief A reusable connection to a CaosDBServer.
diff --git a/include/caosdb/constants.h.in b/include/caosdb/constants.h.in
index bfec36bfbebf91fcd3e9eed38dd9ff305afc7a74..a42c9dfd563df0a340553daf3cbcf3726bf0054e 100644
--- a/include/caosdb/constants.h.in
+++ b/include/caosdb/constants.h.in
@@ -22,22 +22,25 @@
 
 #ifndef CAOSDB_CONSTANTS_H
 #define CAOSDB_CONSTANTS_H
+#ifndef __GNUC__
+#  define  __attribute__(x)
+#endif
 #ifdef __cplusplus
 namespace caosdb {
 #endif
 // clang-format off
-const int LIBCAOSDB_VERSION_MAJOR = @libcaosdb_VERSION_MAJOR@;
-const int LIBCAOSDB_VERSION_MINOR = @libcaosdb_VERSION_MINOR@;
-const int LIBCAOSDB_VERSION_PATCH = @libcaosdb_VERSION_PATCH@;
-const int COMPATIBLE_SERVER_VERSION_MAJOR = @libcaosdb_COMPATIBLE_SERVER_VERSION_MAJOR@;
-const int COMPATIBLE_SERVER_VERSION_MINOR = @libcaosdb_COMPATIBLE_SERVER_VERSION_MINOR@;
-const int COMPATIBLE_SERVER_VERSION_PATCH = @libcaosdb_COMPATIBLE_SERVER_VERSION_PATCH@;
-const char* COMPATIBLE_SERVER_VERSION_PRE_RELEASE = "@libcaosdb_COMPATIBLE_SERVER_VERSION_PRE_RELEASE@";
+static const int LIBCAOSDB_VERSION_MAJOR = @libcaosdb_VERSION_MAJOR@;
+static const int LIBCAOSDB_VERSION_MINOR = @libcaosdb_VERSION_MINOR@;
+static const int LIBCAOSDB_VERSION_PATCH = @libcaosdb_VERSION_PATCH@;
+static const int COMPATIBLE_SERVER_VERSION_MAJOR = @libcaosdb_COMPATIBLE_SERVER_VERSION_MAJOR@;
+static const int COMPATIBLE_SERVER_VERSION_MINOR = @libcaosdb_COMPATIBLE_SERVER_VERSION_MINOR@;
+static const int COMPATIBLE_SERVER_VERSION_PATCH = @libcaosdb_COMPATIBLE_SERVER_VERSION_PATCH@;
+__attribute__((unused)) static const char* COMPATIBLE_SERVER_VERSION_PRE_RELEASE = "@libcaosdb_COMPATIBLE_SERVER_VERSION_PRE_RELEASE@";
 
 /**
  * Precedence of configuration files from highest to lowest.
  */
-const char* LIBCAOSDB_CONFIGURATION_FILES_PRECEDENCE[] = {
+__attribute__((unused)) static const char* LIBCAOSDB_CONFIGURATION_FILES_PRECEDENCE[] = {
   "$CAOSDB_CLIENT_CONFIGURATION",
   "caosdb_client.json",
   "caosdb-client.json",
diff --git a/include/caosdb/entity.h b/include/caosdb/entity.h
index a46c01616a737a6aec114d94fdb76e3c902f62e9..11955fc91330c435bdc348f2bb5c6ed15aef37b0 100644
--- a/include/caosdb/entity.h
+++ b/include/caosdb/entity.h
@@ -36,14 +36,13 @@
 #include "caosdb/protobuf_helper.h"                    // for get_arena
 #include "caosdb/status_code.h"                        // for StatusCode
 #include "caosdb/value.h"                              // for Value
-#include <boost/filesystem/operations.hpp>             // for exists, is_di...
-#include <boost/filesystem/path.hpp>                   // for path
 #include <boost/log/core/record.hpp>                   // for record
 #include <boost/log/detail/attachable_sstream_buf.hpp> // for basic_ostring...
 #include <boost/log/sources/record_ostream.hpp>        // for basic_record_...
 #include <boost/preprocessor/seq/limits/enum_256.hpp>  // for BOOST_PP_SEQ_...
 #include <boost/preprocessor/seq/limits/size_256.hpp>  // for BOOST_PP_SEQ_...
 #include <cstdint>                                     // for int64_t
+#include <filesystem>                                  // for path
 #include <google/protobuf/arena.h>                     // for Arena
 #include <google/protobuf/message.h>                   // for RepeatedPtrField
 #include <iosfwd>                                      // for streamsize
@@ -56,9 +55,9 @@
 #include <vector>                                      // for vector
 
 namespace caosdb::entity {
-using boost::filesystem::exists;
-using boost::filesystem::is_directory;
 using caosdb::entity::v1::IdResponse;
+using std::filesystem::exists;
+using std::filesystem::is_directory;
 using ProtoParent = caosdb::entity::v1::Parent;
 using ProtoProperty = caosdb::entity::v1::Property;
 using ProtoEntity = caosdb::entity::v1::Entity;
@@ -114,7 +113,7 @@ const std::map<Role, std::string> role_names = {{Role::UNSPECIFIED, "UNSPECIFIED
 struct FileDescriptor {
   FileTransmissionId *file_transmission_id;
   ProtoFileDescriptor *wrapped;
-  boost::filesystem::path local_path;
+  std::filesystem::path local_path;
 };
 
 /**
@@ -776,7 +775,7 @@ public:
     this->value = other.value;
     this->properties = other.properties;
     this->parents = other.parents;
-    this->file_descriptor.local_path = boost::filesystem::path(other.file_descriptor.local_path);
+    this->file_descriptor.local_path = std::filesystem::path(other.file_descriptor.local_path);
     this->file_descriptor.file_transmission_id->CopyFrom(
       *other.file_descriptor.file_transmission_id);
     this->file_descriptor.wrapped->CopyFrom(*other.file_descriptor.wrapped);
@@ -871,11 +870,11 @@ public:
 
   inline auto GetFileDescriptor() -> FileDescriptor & { return this->file_descriptor; }
 
-  inline auto GetLocalPath() const noexcept -> const boost::filesystem::path & {
+  inline auto GetLocalPath() const noexcept -> const std::filesystem::path & {
     return this->file_descriptor.local_path;
   }
 
-  inline auto SetLocalPath(const boost::filesystem::path &local_path) noexcept -> StatusCode {
+  inline auto SetLocalPath(const std::filesystem::path &local_path) noexcept -> StatusCode {
     if (GetRole() != Role::FILE) {
       CAOSDB_LOG_WARN(logger_name) << "Entity::SetLocalPath failed. This is not a file entity.";
       return StatusCode::NOT_A_FILE_ENTITY;
diff --git a/include/caosdb/file_transmission/file_reader.h b/include/caosdb/file_transmission/file_reader.h
index 5820c1e9294c76f0f777a6e7cfae9cde7ebf490f..14f8614896de79b15e9bb793a04ac17f40f27fec 100644
--- a/include/caosdb/file_transmission/file_reader.h
+++ b/include/caosdb/file_transmission/file_reader.h
@@ -49,21 +49,19 @@
 #ifndef CAOSDB_FILE_TRANSMISSION_FILE_READER_H
 #define CAOSDB_FILE_TRANSMISSION_FILE_READER_H
 
-#include <boost/filesystem/fstream.hpp>    // for ifstream
-#include <boost/filesystem/operations.hpp> // for exists
-#include <boost/filesystem/path.hpp>       // for path
-#include <cstddef>                         // for size_t
-#include <fstream>                         // for ifstream, size_t
-#include <string>                          // for string
+#include <cstddef>    // for size_t
+#include <filesystem> // for ifstream
+#include <fstream>    // for ifstream, size_t
+#include <string>     // for string
 
 namespace caosdb::transaction {
-using boost::filesystem::exists;
-using boost::filesystem::ifstream;
-using boost::filesystem::path;
+using std::ifstream;
+using std::filesystem::exists;
+using std::filesystem::path;
 
 class FileReader final {
 public:
-  FileReader(boost::filesystem::path filename);
+  FileReader(std::filesystem::path filename);
 
   ~FileReader() = default;
 
@@ -81,7 +79,7 @@ private:
   void openFile();
 
   std::ifstream stream_;
-  boost::filesystem::path filename_;
+  std::filesystem::path filename_;
   unsigned long long size_;
 };
 
diff --git a/include/caosdb/file_transmission/file_writer.h b/include/caosdb/file_transmission/file_writer.h
index 801d74b9547951d2a3b86ed4b333bfb4b7035aa9..165178b1e3b44f9d3208220d1422af1bb61d0833 100644
--- a/include/caosdb/file_transmission/file_writer.h
+++ b/include/caosdb/file_transmission/file_writer.h
@@ -49,15 +49,15 @@
 #ifndef CAOSDB_FILE_TRANSMISSION_FILE_WRITER_H
 #define CAOSDB_FILE_TRANSMISSION_FILE_WRITER_H
 
-#include <boost/filesystem/path.hpp> // for path
-#include <fstream>                   // for ofstream
-#include <string>                    // for string
+#include <filesystem> // for path
+#include <fstream>    // for ofstream
+#include <string>     // for string
 
 namespace caosdb::transaction {
 
 class FileWriter final {
 public:
-  FileWriter(boost::filesystem::path filename);
+  FileWriter(std::filesystem::path filename);
 
   ~FileWriter() = default;
 
@@ -73,7 +73,7 @@ private:
   void openFile();
 
   std::ofstream stream_;
-  boost::filesystem::path filename_;
+  std::filesystem::path filename_;
 };
 
 } // namespace caosdb::transaction
diff --git a/include/caosdb/protobuf_helper.h b/include/caosdb/protobuf_helper.h
index 55a229b697eeac5d292d9e4d73296665fb44c7ef..ef4cb8383eb384cd058a3f210c9d27f99b199658 100644
--- a/include/caosdb/protobuf_helper.h
+++ b/include/caosdb/protobuf_helper.h
@@ -22,9 +22,8 @@
 #ifndef CAOSDB_PROTOBUF_HELPER_H
 #define CAOSDB_PROTOBUF_HELPER_H
 
-#include <google/protobuf/arena.h> // for Arena
-// IWYU pragma: no_include "google/protobuf/extension_set.h"
-// IWYU pragma: no_include "google/protobuf/generated_message_util.h"
+// IWYU pragma: no_include <google/protobuf/extension_set.h>
+#include <google/protobuf/arena.h>          // for Arena
 #include <google/protobuf/util/json_util.h> // for JsonOptions, MessageToJs...
 #include <string>                           // for string
 
diff --git a/include/caosdb/status_code.h b/include/caosdb/status_code.h
index e1a382191b5bd4559c554e2fc3e084103c27c3cc..41dad5bddd918ac5cc42e577798676bcf8b6bea4 100644
--- a/include/caosdb/status_code.h
+++ b/include/caosdb/status_code.h
@@ -67,7 +67,7 @@ enum StatusCode {
   TRANSACTION_TYPE_ERROR = 26,
   UNSUPPORTED_FEATURE = 27,
   ORIGINAL_ENTITY_MISSING_ID = 28,
-  EXTERN_C_ASSIGNMENT_ERROR = 29,
+  // EXTERN_C_ASSIGNMENT_ERROR = 29,
   ENTITY_CANNOT_HAVE_A_DATA_TYPE = 30,
   ENTITY_CANNOT_HAVE_A_VALUE = 31,
   NOT_A_FILE_ENTITY = 32,
diff --git a/include/caosdb/transaction.h b/include/caosdb/transaction.h
index 3ff5e077f4aa144c7dfa453ce13fe1a01836810e..6fc429ad0cb10c9df88c705e2874834da628ff6f 100644
--- a/include/caosdb/transaction.h
+++ b/include/caosdb/transaction.h
@@ -55,12 +55,12 @@
     return StatusCode::TRANSACTION_STATUS_ERROR;                                                   \
   }                                                                                                \
   switch (this->transaction_type) {                                                                \
-  case NONE:                                                                                       \
+  case TransactionType::NONE:                                                                      \
     this->transaction_type = TransactionType::READ_ONLY;                                           \
     break;                                                                                         \
-  case READ_ONLY:                                                                                  \
+  case TransactionType::READ_ONLY:                                                                 \
     break;                                                                                         \
-  case MIXED_READ_AND_WRITE:                                                                       \
+  case TransactionType::MIXED_READ_AND_WRITE:                                                      \
     break;                                                                                         \
   default:                                                                                         \
     CAOSDB_LOG_ERROR_AND_RETURN_STATUS(                                                            \
@@ -91,11 +91,11 @@
     return StatusCode::TRANSACTION_STATUS_ERROR;                                                   \
   }                                                                                                \
   switch (this->transaction_type) {                                                                \
-  case NONE:                                                                                       \
+  case TransactionType::NONE:                                                                      \
     this->transaction_type = TransactionType::MIXED_WRITE;                                         \
-  case DELETE:                                                                                     \
-  case MIXED_WRITE:                                                                                \
-  case MIXED_READ_AND_WRITE:                                                                       \
+  case TransactionType::DELETE_ONLY:                                                               \
+  case TransactionType::MIXED_WRITE:                                                               \
+  case TransactionType::MIXED_READ_AND_WRITE:                                                      \
     break;                                                                                         \
   default:                                                                                         \
     CAOSDB_LOG_ERROR_AND_RETURN_STATUS(                                                            \
@@ -113,11 +113,11 @@
     return StatusCode::TRANSACTION_STATUS_ERROR;                                                   \
   }                                                                                                \
   switch (this->transaction_type) {                                                                \
-  case NONE:                                                                                       \
+  case TransactionType::NONE:                                                                      \
     this->transaction_type = TransactionType::MIXED_WRITE;                                         \
-  case INSERT:                                                                                     \
-  case MIXED_WRITE:                                                                                \
-  case MIXED_READ_AND_WRITE:                                                                       \
+  case TransactionType::INSERT_ONLY:                                                               \
+  case TransactionType::MIXED_WRITE:                                                               \
+  case TransactionType::MIXED_READ_AND_WRITE:                                                      \
     break;                                                                                         \
   default:                                                                                         \
     CAOSDB_LOG_ERROR_AND_RETURN_STATUS(                                                            \
@@ -135,11 +135,11 @@
     return StatusCode::TRANSACTION_STATUS_ERROR;                                                   \
   }                                                                                                \
   switch (this->transaction_type) {                                                                \
-  case NONE:                                                                                       \
+  case TransactionType::NONE:                                                                      \
     this->transaction_type = TransactionType::MIXED_WRITE;                                         \
-  case UPDATE:                                                                                     \
-  case MIXED_WRITE:                                                                                \
-  case MIXED_READ_AND_WRITE:                                                                       \
+  case TransactionType::UPDATE_ONLY:                                                               \
+  case TransactionType::MIXED_WRITE:                                                               \
+  case TransactionType::MIXED_READ_AND_WRITE:                                                      \
     break;                                                                                         \
   default:                                                                                         \
     CAOSDB_LOG_ERROR_AND_RETURN_STATUS(                                                            \
@@ -287,9 +287,9 @@ public:
   enum TransactionType {
     NONE,                //!< Unspecified or not specified yet.
     READ_ONLY,           //!< Only retrievals (by id, by query)
-    INSERT,              //!< Only insertions
-    UPDATE,              //!< Only updates
-    DELETE,              //!< Only deletions
+    INSERT_ONLY,         //!< Only insertions
+    UPDATE_ONLY,         //!< Only updates
+    DELETE_ONLY,         //!< Only deletions
     MIXED_WRITE,         //!< Only insertions, deletions, updates
     MIXED_READ_AND_WRITE //!< all kind of transaction.
   };
diff --git a/include/caosdb/utility.h b/include/caosdb/utility.h
index 5af1b491c0b5b9d48606ba6b46130b3ef3de1d9c..0a4d65e883ccfb6cc8f41d1c412bef5433b89417 100644
--- a/include/caosdb/utility.h
+++ b/include/caosdb/utility.h
@@ -25,15 +25,13 @@
 #include "caosdb/entity.h"                    // for Importance, Role
 #include <boost/beast/core/detail/base64.hpp> // for encoded_size
 #include <boost/beast/core/detail/base64.ipp> // for encode
-#include <boost/filesystem/operations.hpp>    // for exists
-#include <boost/filesystem/path.hpp>          // for path
-#include <boost/filesystem/fstream.hpp>       // for basic_ifstream, ifstream
 #include <boost/filesystem/string_file.hpp>   // for load_string_file
 #include <boost/json/stream_parser.hpp>       // for stream_parser
 #include <boost/json/value.hpp>               // for value
 #include <boost/lexical_cast.hpp>             // for lexical_cast
 #include <cassert>                            // for assert
 #include <cstdlib>                            // for getenv
+#include <filesystem>                         // for path
 #include <fstream>                            // for basic_istream<>::__ist...
 #include <memory>                             // for allocator, unique_ptr
 #include <stdexcept>                          // for logic_error
@@ -42,11 +40,11 @@
 #include <typeinfo>                           // for type_info
 
 namespace caosdb::utility {
-using boost::filesystem::exists;
-using boost::filesystem::ifstream;
-using boost::filesystem::path;
 using boost::json::stream_parser;
 using boost::json::value;
+using std::ifstream;
+using std::filesystem::exists;
+using std::filesystem::path;
 
 /**
  * @brief Get the name of the enum value.  May be useful for higher-order CaosDB clients.
@@ -86,9 +84,9 @@ auto getEnumValueFromName<caosdb::entity::Role>(const std::string &name) -> caos
 /**
  * @brief Read a text file into a string and return the file's content.
  */
-inline auto load_string_file(const path &path) -> std::string {
+inline auto load_string_file(const path &file_path) -> std::string {
   std::string result;
-  boost::filesystem::load_string_file(path, result);
+  boost::filesystem::load_string_file(file_path.string(), result);
   return result;
 }
 
diff --git a/include/ccaosdb.h b/include/ccaosdb.h
index 4d1b99dd151fbf09a53d9b80c0963ee3d3368c67..48d0da757351508ed194e52635670d0c24e53164 100644
--- a/include/ccaosdb.h
+++ b/include/ccaosdb.h
@@ -20,10 +20,14 @@
  *
  */
 
-#include <cstdint> // for int64_t
-
+#ifndef CCAOSDB_H
+#define CCAOSDB_H
 #ifdef __cplusplus
+#include <cstdint> // for int64_t
 extern "C" {
+#else
+#include <stdint.h>  // for int64_t
+#include <stdbool.h> // for bool
 #endif
 
 /**
@@ -70,7 +74,7 @@ int caosdb_status_code_OTHER_CLIENT_ERROR();
  */
 typedef struct caosdb_connection_connection {
   void *wrapped_connection;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_connection_connection;
 
 /**
@@ -82,7 +86,7 @@ typedef struct caosdb_connection_connection {
  */
 typedef struct caosdb_connection_connection_configuration {
   void *wrapped_connection_configuration;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_connection_connection_configuration;
 
 /**
@@ -102,12 +106,12 @@ typedef struct caosdb_info_version_info {
 
 typedef struct caosdb_connection_certificate_provider {
   void *wrapped_certificate_provider;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_connection_certificate_provider;
 
 typedef struct caosdb_authentication_authenticator {
   void *wrapped_authenticator;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_authentication_authenticator;
 
 /**
@@ -266,7 +270,7 @@ int caosdb_connection_connection_manager_get_connection(caosdb_connection_connec
 
 typedef struct caosdb_transaction_transaction {
   void *wrapped_transaction;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_transaction_transaction;
 
 /**
@@ -292,12 +296,12 @@ int caosdb_transaction_transaction_execute(caosdb_transaction_transaction *trans
 
 typedef struct caosdb_transaction_result_set {
   void *wrapped_result_set;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_transaction_result_set;
 
 typedef struct caosdb_entity_entity {
   void *wrapped_entity;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_entity_entity;
 
 int caosdb_transaction_transaction_get_result_set(caosdb_transaction_transaction *transaction,
@@ -348,27 +352,27 @@ int caosdb_transaction_transaction_delete_by_id(caosdb_transaction_transaction *
 
 typedef struct caosdb_entity_property {
   void *wrapped_property;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_entity_property;
 
 typedef struct caosdb_entity_parent {
   void *wrapped_parent;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_entity_parent;
 
 typedef struct caosdb_entity_message {
   void *wrapped_message;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_entity_message;
 
 typedef struct caosdb_entity_value {
   void *wrapped_value;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_entity_value;
 
 typedef struct caosdb_entity_datatype {
   void *wrapped_datatype;
-  bool _deletable = false;
+  bool _deletable;
 } caosdb_entity_datatype;
 
 // GETTERS FOR EVERYTHING
@@ -494,3 +498,4 @@ int caosdb_entity_parent_set_name(caosdb_entity_parent *parent, const char *name
 #ifdef __cplusplus
 }
 #endif
+#endif
diff --git a/src/caosdb/configuration.cpp b/src/caosdb/configuration.cpp
index aa35901c9bd116dba17c4ceed164e4ccbac6dfe7..90cc97b3cebc1b39a1b376805ae73cc068173ef7 100644
--- a/src/caosdb/configuration.cpp
+++ b/src/caosdb/configuration.cpp
@@ -26,9 +26,6 @@
 #include "caosdb/log_level.h"                          // for CAOSDB_DEFAULT...
 #include "caosdb/status_code.h"                        // for StatusCode
 #include "caosdb/utility.h"                            // for get_home_direc...
-#include <boost/filesystem/operations.hpp>             // for exists
-#include <boost/filesystem/path.hpp>                   // for path, path::i...
-#include <boost/iterator/iterator_facade.hpp>          // for iterator_facad...
 #include <boost/json/impl/object.hpp>                  // for object::at
 #include <boost/json/object.hpp>                       // for object, objec...
 #include <boost/json/string.hpp>                       // for string
@@ -46,15 +43,13 @@
 #include <exception>                                   // IWYU pragma: keep
 // IWYU pragma: no_include <bits/exception.h>
 #include <grpcpp/security/credentials.h> // for SslCredentials
-#include <iostream>
-#include <iterator>  // for next
-#include <map>       // for map
-#include <stdexcept> // for out_of_range
-#include <string>    // for string, operator+
+#include <iterator>                      // for next
+#include <map>                           // for map
+#include <sstream>                       // for basic_stringb...
+#include <stdexcept>                     // for out_of_range
+#include <string>                        // for string, operator+
 
 namespace caosdb::configuration {
-using boost::filesystem::exists;
-using boost::filesystem::path;
 using boost::json::object;
 using boost::json::value;
 using caosdb::authentication::Authenticator;
@@ -72,6 +67,8 @@ using caosdb::utility::load_string_file;
 using grpc::InsecureChannelCredentials;
 using grpc::SslCredentials;
 using grpc::SslCredentialsOptions;
+using std::filesystem::exists;
+using std::filesystem::path;
 
 PemFileCertificateProvider::PemFileCertificateProvider(const path &path) {
   this->certificate_provider = load_string_file(path);
@@ -477,12 +474,12 @@ auto ConfigurationManager::InitializeDefaults() -> int { // NOLINT
       configuration_file_path = std::make_unique<path>();
       const path raw(configuration_file);
       // resolve home directory
-      for (auto segment = raw.begin(); segment != raw.end(); ++segment) {
-        if (segment->string() == "$HOME") {
+      for (const auto &segment : raw) {
+        if (segment.string() == "$HOME") {
           path expanded_home(get_home_directory());
           *configuration_file_path /= expanded_home;
         } else {
-          *configuration_file_path /= *segment;
+          *configuration_file_path /= segment;
         }
       }
       if (exists(*configuration_file_path)) {
diff --git a/src/caosdb/file_transmission/download_request_handler.cpp b/src/caosdb/file_transmission/download_request_handler.cpp
index e915075bdc5c8583c3e2ed2a5b7d979811e34942..23520e0d78c5c8c8606ad5acf7611ba7c4806fc4 100644
--- a/src/caosdb/file_transmission/download_request_handler.cpp
+++ b/src/caosdb/file_transmission/download_request_handler.cpp
@@ -51,7 +51,6 @@
 #include "caosdb/protobuf_helper.h"                    // for get_arena
 #include "caosdb/status_code.h"                        // for GENERIC_RPC_E...
 #include "caosdb/transaction_status.h"                 // for TransactionStatus
-#include <boost/filesystem/path.hpp>                   // for operator<<, path
 #include <boost/log/core/record.hpp>                   // for record
 #include <boost/log/detail/attachable_sstream_buf.hpp> // for basic_ostring...
 #include <boost/log/sources/record_ostream.hpp>        // for basic_record_...
@@ -59,13 +58,14 @@
 #include <boost/preprocessor/seq/limits/size_256.hpp>  // for BOOST_PP_SEQ_...
 #include <exception>                                   // IWYU pragma: keep
 // IWYU pragma: no_include <bits/exception.h>
+#include <filesystem>                             // for operator<<, path
 #include <google/protobuf/arena.h>                // for Arena
 #include <grpcpp/impl/codegen/async_stream.h>     // for ClientAsyncRe...
 #include <grpcpp/impl/codegen/client_context.h>   // for ClientContext
 #include <grpcpp/impl/codegen/completion_queue.h> // for CompletionQueue
 #include <grpcpp/impl/codegen/status.h>           // for Status
 #include <grpcpp/impl/codegen/status_code_enum.h> // for OK, UNAUTHENT...
-#include <iostream>                               // for char_traits
+#include <sstream>                                // for streamsize
 #include <stdexcept>                              // for runtime_error
 #include <string>                                 // for string, opera...
 #include <utility>                                // for move
diff --git a/src/caosdb/file_transmission/file_reader.cpp b/src/caosdb/file_transmission/file_reader.cpp
index 1a78e5a76513ae0aaf94b2ae4967af5d7b66e0c0..e943153ca7cfcc87907ed88afb1995ad31cde71d 100644
--- a/src/caosdb/file_transmission/file_reader.cpp
+++ b/src/caosdb/file_transmission/file_reader.cpp
@@ -48,13 +48,12 @@
  */
 #include "caosdb/file_transmission/file_reader.h"
 #include "caosdb/file_transmission/file_error.h" // for FileIOError
-#include <boost/filesystem/path.hpp>             // for path
+#include <filesystem>                            // for path
 #include <utility>                               // for move
 
 namespace caosdb::transaction {
 
-FileReader::FileReader(boost::filesystem::path filename)
-  : filename_(std::move(filename)), size_(0) {
+FileReader::FileReader(std::filesystem::path filename) : filename_(std::move(filename)), size_(0) {
   this->openFile();
 }
 
diff --git a/src/caosdb/file_transmission/file_writer.cpp b/src/caosdb/file_transmission/file_writer.cpp
index 2c7f2a6000718366f846a4be61dd5c2144370a65..0f0161fbcafe1df7f6ffa271dcce8af9cc10fe82 100644
--- a/src/caosdb/file_transmission/file_writer.cpp
+++ b/src/caosdb/file_transmission/file_writer.cpp
@@ -48,12 +48,12 @@
  */
 #include "caosdb/file_transmission/file_writer.h"
 #include "caosdb/file_transmission/file_error.h" // for FileIOError
-#include <boost/filesystem/path.hpp>             // for path
+#include <filesystem>                            // for path
 #include <utility>                               // for move
 
 namespace caosdb::transaction {
 
-FileWriter::FileWriter(boost::filesystem::path filename) : filename_(std::move(filename)) {
+FileWriter::FileWriter(std::filesystem::path filename) : filename_(std::move(filename)) {
   this->openFile();
 }
 
diff --git a/src/caosdb/file_transmission/upload_request_handler.cpp b/src/caosdb/file_transmission/upload_request_handler.cpp
index bc74391753a0c7c3dce01f80d8fa67acc9e782cd..71f1106b78397a435638a0a1695bb86cb02a3edc 100644
--- a/src/caosdb/file_transmission/upload_request_handler.cpp
+++ b/src/caosdb/file_transmission/upload_request_handler.cpp
@@ -52,7 +52,6 @@
 #include "caosdb/status_code.h"                        // for GENERIC_RPC_E...
 #include "caosdb/transaction_status.h"                 // for TransactionStatus
 #include <algorithm>                                   // for min
-#include <boost/filesystem/path.hpp>                   // for operator<<, path
 #include <boost/log/core/record.hpp>                   // for record
 #include <boost/log/detail/attachable_sstream_buf.hpp> // for basic_ostring...
 #include <boost/log/sources/record_ostream.hpp>        // for basic_record_...
@@ -61,6 +60,7 @@
 #include <cstdint>                                     // for uint64_t
 #include <exception>                                   // IWYU pragma: keep
 // IWYU pragma: no_include <bits/exception.h>
+#include <filesystem>                             // for operator<<, path
 #include <google/protobuf/arena.h>                // for Arena
 #include <grpcpp/impl/codegen/async_stream.h>     // for ClientAsyncWr...
 #include <grpcpp/impl/codegen/call_op_set.h>      // for WriteOptions
@@ -68,7 +68,7 @@
 #include <grpcpp/impl/codegen/completion_queue.h> // for CompletionQueue
 #include <grpcpp/impl/codegen/status.h>           // for Status
 #include <grpcpp/impl/codegen/status_code_enum.h> // for OK, UNAUTHENT...
-#include <iostream>                               // for endl, streamsize
+#include <sstream>                                // for streamsize
 #include <string>                                 // for basic_string
 #include <utility>                                // for move
 
diff --git a/src/caosdb/logging.cpp b/src/caosdb/logging.cpp
index ead331da4f91d0053d413846158425f2bdb0667e..51b4118515b4ddeda10411e5966b03c21f29449e 100644
--- a/src/caosdb/logging.cpp
+++ b/src/caosdb/logging.cpp
@@ -26,6 +26,7 @@
 #include <boost/log/attributes/clock.hpp>
 #include <boost/log/core/core.hpp> // for core
 #include <boost/log/core/record.hpp>
+#include <boost/log/sources/global_logger_storage.hpp>
 #include <boost/log/sources/record_ostream.hpp>
 #include <boost/log/sources/severity_channel_logger.hpp>
 #include <boost/log/utility/setup/from_settings.hpp>
diff --git a/src/caosdb/status_code_description.cpp b/src/caosdb/status_code_description.cpp
index 5823943cfd7f79416cabb61662f778bac5de9bf8..a18c3fbcba3c93f66b837bbfe0d7e0ff725ff4ca 100644
--- a/src/caosdb/status_code_description.cpp
+++ b/src/caosdb/status_code_description.cpp
@@ -152,9 +152,9 @@ auto get_status_description(int code) -> const std::string & {
     {StatusCode::FILE_UPLOAD_ERROR, "The transaction failed during the upload of the files"},
     {StatusCode::UNSUPPORTED_FEATURE,
      "This feature is not available in the this client implementation."},
-    {StatusCode::EXTERN_C_ASSIGNMENT_ERROR,
-     "You tried to assign a new object to the wrapped void pointer. You have "
-     "to delete the old pointee first."},
+    //{StatusCode::EXTERN_C_ASSIGNMENT_ERROR,
+    //"You tried to assign a new object to the wrapped void pointer. You have "
+    //"to delete the old pointee first."},
     {StatusCode::ENUM_MAPPING_ERROR,
      "The role, importance, or datatype you specified does not exist."},
     {StatusCode::SPOILED,
diff --git a/src/caosdb/transaction.cpp b/src/caosdb/transaction.cpp
index 99569d07d89b45da10c4e0f71a68ddbec7f4c130..5ed366ac4285511fc1907b8b1db06628fd35359f 100644
--- a/src/caosdb/transaction.cpp
+++ b/src/caosdb/transaction.cpp
@@ -28,7 +28,6 @@
 #include "caosdb/status_code.h"                                    // for StatusCode
 #include "caosdb/transaction_handler.h"                            // for EntityTransactionHandler
 #include <algorithm>                                               // for max
-#include <boost/filesystem/path.hpp>                               // for operator<<, path
 #include <boost/log/core/record.hpp>                               // for record
 #include <boost/log/detail/attachable_sstream_buf.hpp>             // for basic_ostring...
 #include <boost/log/sources/record_ostream.hpp>                    // for basic_record_...
@@ -36,13 +35,14 @@
 #include <boost/preprocessor/seq/limits/size_256.hpp>              // for BOOST_PP_SEQ_...
 // IWYU pragma: no_include <bits/exception.h>
 #include <exception>                              // IWYU pragma: keep
+#include <filesystem>                             // for operator<<, path
 #include <google/protobuf/arena.h>                // for Arena
 #include <grpc/impl/codegen/gpr_types.h>          // for gpr_timespec
 #include <grpcpp/impl/codegen/completion_queue.h> // for CompletionQueue
-#include <iosfwd>                                 // for streamsize
 #include <map>                                    // for map, operator!=
 #include <memory>                                 // for unique_ptr
-#include <utility>                                // for move, pair
+#include <sstream>
+#include <utility> // for move, pair
 
 namespace caosdb::transaction {
 using caosdb::entity::v1::EntityTransactionService;
@@ -195,7 +195,7 @@ auto Transaction::ExecuteAsynchronously() noexcept -> StatusCode { // NOLINT
   case MIXED_READ_AND_WRITE:
     CAOSDB_LOG_ERROR_AND_RETURN_STATUS(
       logger_name, StatusCode::UNSUPPORTED_FEATURE,
-      "MIXED_WRITE UNSUPPORTED: The current implementation does not support "
+      "MIXED_READ_AND_WRITE UNSUPPORTED: The current implementation does not support "
       "mixed read and write transactions (containing retrievals, insertions, "
       "deletions, and updates in one transaction).")
   default:
diff --git a/src/ccaosdb.cpp b/src/ccaosdb.cpp
index 77759fce1d216f215dfccd343aa8202b2ec911fa..ae1a728f62b7cdfb293eb347d1a1966b86bfd3b2 100644
--- a/src/ccaosdb.cpp
+++ b/src/ccaosdb.cpp
@@ -58,11 +58,6 @@ extern "C" {
 #define ENUM_VALUE_FROM_NAME(arg, etype)                                                           \
   caosdb::utility::getEnumValueFromName<caosdb::entity::etype>(arg)
 
-#define RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(name)                                                \
-  if (name->_deletable) {                                                                          \
-    return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;                                          \
-  }
-
 /*
  * Macro for wrapping every function into a try-catch clause. If an exception
  * occurs, the given StatusCode is being returned.
@@ -163,7 +158,6 @@ extern "C" {
 #define CREATE_VALUE(fname, arg)                                                                   \
   ERROR_RETURN_CODE(GENERIC_ERROR,                                                                 \
                     int caosdb_entity_create_##fname(caosdb_entity_value *out, arg), {             \
-                      RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)                                   \
                       out->wrapped_value = new caosdb::entity::Value(value);                       \
                       out->_deletable = true;                                                      \
                       return 0;                                                                    \
@@ -175,9 +169,6 @@ extern "C" {
   ERROR_RETURN_CODE(                                                                               \
     GENERIC_ERROR,                                                                                 \
     int caosdb_entity_create_##fname(caosdb_entity_value *out, arg, const int length), {           \
-      if (out->_deletable) {                                                                       \
-        return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;                                      \
-      }                                                                                            \
       std::vector<type> value_vec;                                                                 \
       for (int i = 0; i < length; i++) {                                                           \
         value_vec.push_back(assign);                                                               \
@@ -245,9 +236,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_create_pem_file_certificate_provider(
                     caosdb_connection_certificate_provider *out, const char *path),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     out->wrapped_certificate_provider =
                       new caosdb::configuration::PemFileCertificateProvider(std::string(path));
                     out->_deletable = true;
@@ -258,10 +246,11 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_delete_certificate_provider(
                     caosdb_connection_certificate_provider *provider),
                   {
-                    if (provider->_deletable) {
+                    if (provider->_deletable && provider->wrapped_certificate_provider) {
                       delete static_cast<caosdb::configuration::CertificateProvider *>(
                         provider->wrapped_certificate_provider);
                     }
+                    provider->wrapped_certificate_provider = nullptr;
                     provider->_deletable = false;
                     return 0;
                   })
@@ -271,9 +260,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                     caosdb_authentication_authenticator *out, const char *username,
                     const char *password),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     out->wrapped_authenticator =
                       new caosdb::authentication::PlainPasswordAuthenticator(std::string(username),
                                                                              std::string(password));
@@ -285,10 +271,11 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_authentication_delete_authenticator(
                     caosdb_authentication_authenticator *authenticator),
                   {
-                    if (authenticator->_deletable) {
+                    if (authenticator->_deletable && authenticator->wrapped_authenticator) {
                       delete static_cast<caosdb::authentication::Authenticator *>(
                         authenticator->wrapped_authenticator);
                     }
+                    authenticator->wrapped_authenticator = nullptr;
                     authenticator->_deletable = false;
                     return 0;
                   })
@@ -300,9 +287,6 @@ ERROR_RETURN_CODE(
     caosdb_authentication_authenticator *authenticator,
     caosdb_connection_certificate_provider *provider),
   {
-    if (out->_deletable) {
-      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-    }
     auto host_str = std::string(host);
     if (authenticator != nullptr && provider != nullptr) {
       auto wrapped_provider = static_cast<caosdb::configuration::CertificateProvider *>(
@@ -334,9 +318,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                     caosdb_connection_connection_configuration *out, const char *host,
                     const int port),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     out->wrapped_connection_configuration =
                       new caosdb::configuration::InsecureConnectionConfiguration(host, port);
                     out->_deletable = true;
@@ -347,10 +328,12 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_delete_connection_configuration(
                     caosdb_connection_connection_configuration *configuration),
                   {
-                    if (configuration->_deletable) {
+                    if (configuration->_deletable &&
+                        configuration->wrapped_connection_configuration) {
                       delete static_cast<caosdb::configuration::ConnectionConfiguration *>(
                         configuration->wrapped_connection_configuration);
                     }
+                    configuration->wrapped_connection_configuration = nullptr;
                     configuration->_deletable = false;
                     return 0;
                   })
@@ -360,9 +343,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                     caosdb_connection_connection *out,
                     const caosdb_connection_connection_configuration *configuration),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     caosdb::configuration::ConnectionConfiguration *config =
                       static_cast<caosdb::configuration::ConnectionConfiguration *>(
                         configuration->wrapped_connection_configuration);
@@ -374,10 +354,11 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
 ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_delete_connection(caosdb_connection_connection *connection),
                   {
-                    if (connection->_deletable) {
+                    if (connection->_deletable && connection->wrapped_connection) {
                       delete static_cast<caosdb::connection::Connection *>(
                         connection->wrapped_connection);
                     }
+                    connection->wrapped_connection = nullptr;
                     connection->_deletable = false;
                     return 0;
                   })
@@ -417,9 +398,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_connection_manager_get_default_connection(
                     caosdb_connection_connection *out),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     out->wrapped_connection =
                       caosdb::connection::ConnectionManager::GetDefaultConnection().get();
                     out->_deletable = false;
@@ -430,9 +408,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_connection_manager_get_connection(
                     caosdb_connection_connection *out, const char *name),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     out->wrapped_connection =
                       caosdb::connection::ConnectionManager::GetConnection(std::string(name)).get();
                     // managed by the connection manager now, so not
@@ -448,9 +423,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_connection_connection_create_transaction(
                     caosdb_connection_connection *connection, caosdb_transaction_transaction *out),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_connection =
                       static_cast<caosdb::connection::Connection *>(connection->wrapped_connection);
                     out->wrapped_transaction = wrapped_connection->CreateTransaction().release();
@@ -461,9 +433,11 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
 ERROR_RETURN_CODE(
   GENERIC_ERROR,
   int caosdb_transaction_delete_transaction(caosdb_transaction_transaction *transaction), {
-    if (transaction->_deletable) {
+    if (transaction->_deletable && transaction->wrapped_transaction) {
       delete static_cast<caosdb::transaction::Transaction *>(transaction->wrapped_transaction);
     }
+    transaction->wrapped_transaction = nullptr;
+    transaction->_deletable = false;
     return 0;
   })
 
@@ -553,9 +527,6 @@ ERROR_RETURN_CODE(
   int caosdb_transaction_transaction_get_result_set(caosdb_transaction_transaction *transaction,
                                                     caosdb_transaction_result_set *out),
   {
-    if (out->_deletable) {
-      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-    }
     auto *wrapped_transaction =
       static_cast<caosdb::transaction::Transaction *>(transaction->wrapped_transaction);
     out->wrapped_result_set = (void *)(&(wrapped_transaction->GetResultSet()));
@@ -568,9 +539,6 @@ ERROR_RETURN_CODE(
   int caosdb_transaction_transaction_release_result_set(caosdb_transaction_transaction *transaction,
                                                         caosdb_transaction_result_set *out),
   {
-    if (out->_deletable) {
-      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-    }
     auto *wrapped_transaction =
       static_cast<caosdb::transaction::Transaction *>(transaction->wrapped_transaction);
     out->wrapped_result_set = (void *)(wrapped_transaction->ReleaseResultSet());
@@ -582,9 +550,10 @@ ERROR_RETURN_CODE(
 ERROR_RETURN_CODE(
   GENERIC_ERROR,
   int caosdb_transaction_delete_result_set(caosdb_transaction_result_set *result_set), {
-    if (result_set->_deletable) {
+    if (result_set->_deletable && result_set->wrapped_result_set) {
       delete static_cast<caosdb::entity::Entity *>(result_set->wrapped_result_set);
     }
+    result_set->wrapped_result_set = nullptr;
     result_set->_deletable = false;
     return 0;
   })
@@ -615,9 +584,6 @@ ERROR_RETURN_CODE(
   int caosdb_transaction_result_set_release_at(caosdb_transaction_result_set *result_set,
                                                caosdb_entity_entity *entity, int index),
   {
-    if (entity->_deletable) {
-      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-    }
     auto *wrapped_result_set =
       static_cast<caosdb::transaction::MultiResultSet *>(result_set->wrapped_result_set);
     entity->wrapped_entity = wrapped_result_set->release_at(index);
@@ -638,52 +604,46 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_create_entity(caosdb_entity_entity *out), {
-  if (out->_deletable) {
-    return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-  }
   out->wrapped_entity = new caosdb::entity::Entity();
   out->_deletable = true;
   return 0;
 })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_delete_entity(caosdb_entity_entity *out), {
-  if (out->_deletable) {
+  if (out->_deletable && out->wrapped_entity) {
     delete static_cast<caosdb::entity::Entity *>(out->wrapped_entity);
   }
+  out->wrapped_entity = nullptr;
   out->_deletable = false;
   return 0;
 })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_create_property(caosdb_entity_property *out), {
-  if (out->_deletable) {
-    return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-  }
   out->wrapped_property = new caosdb::entity::Property();
   out->_deletable = true;
   return 0;
 })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_delete_property(caosdb_entity_property *out), {
-  if (out->_deletable) {
+  if (out->_deletable && out->wrapped_property) {
     delete static_cast<caosdb::entity::Property *>(out->wrapped_property);
   }
+  out->wrapped_property = nullptr;
   out->_deletable = false;
   return 0;
 })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_create_parent(caosdb_entity_parent *out), {
-  if (out->_deletable) {
-    return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-  }
   out->wrapped_parent = new caosdb::entity::Parent();
   out->_deletable = true;
   return 0;
 })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_delete_parent(caosdb_entity_parent *out), {
-  if (out->_deletable) {
+  if (out->_deletable && out->wrapped_parent) {
     delete static_cast<caosdb::entity::Parent *>(out->wrapped_parent);
   }
+  out->wrapped_parent = nullptr;
   out->_deletable = false;
   return 0;
 })
@@ -692,7 +652,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_create_atomic_datatype(caosdb_entity_datatype *out,
                                                            const char *name),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     try {
                       auto enum_value = ENUM_VALUE_FROM_NAME(std::string(name), AtomicDataType);
                       out->wrapped_datatype = new caosdb::entity::DataType(enum_value);
@@ -707,7 +666,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_create_reference_datatype(caosdb_entity_datatype *out,
                                                               const char *name),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     out->wrapped_datatype = new caosdb::entity::DataType(std::string(name));
                     out->_deletable = true;
                     return 0;
@@ -716,7 +674,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_create_atomic_list_datatype(caosdb_entity_datatype *out,
                                                                 const char *name),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     try {
                       auto enum_value = ENUM_VALUE_FROM_NAME(std::string(name), AtomicDataType);
                       out->wrapped_datatype =
@@ -732,7 +689,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_create_reference_list_datatype(caosdb_entity_datatype *out,
                                                                    const char *name),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     out->wrapped_datatype = new caosdb::entity::DataType(
                       caosdb::entity::DataType::ListOf(std::string(name)));
                     out->_deletable = true;
@@ -740,9 +696,10 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   })
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_delete_datatype(caosdb_entity_datatype *out), {
-  if (out->_deletable) {
+  if (out->_deletable && out->wrapped_datatype) {
     delete WRAPPED_DATATYPE_CAST(out);
   }
+  out->wrapped_datatype = nullptr;
   out->_deletable = false;
   return 0;
 })
@@ -757,9 +714,10 @@ CREATE_VECTOR_VALUE(double_vector_value, double, const double *value, value[i])
 CREATE_VECTOR_VALUE(bool_vector_value, bool, const bool *value, value[i])
 
 ERROR_RETURN_CODE(GENERIC_ERROR, int caosdb_entity_delete_value(caosdb_entity_value *out), {
-  if (out->_deletable) {
+  if (out->_deletable && out->wrapped_value) {
     delete WRAPPED_VALUE_CAST(out);
   }
+  out->wrapped_value = nullptr;
   out->_deletable = false;
   return 0;
 })
@@ -793,7 +751,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_datatype(caosdb_entity_entity *entity,
                                                         caosdb_entity_datatype *out),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     auto *wrapped_entity = WRAPPED_ENTITY_CAST(entity);
                     out->wrapped_datatype = (void *)(&(wrapped_entity->GetDataType()));
                     out->_deletable = false;
@@ -803,7 +760,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_value(caosdb_entity_entity *entity,
                                                      caosdb_entity_value *out),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     auto *wrapped_entity = WRAPPED_ENTITY_CAST(entity);
                     out->wrapped_value = (void *)(&(wrapped_entity->GetValue()));
                     out->_deletable = false;
@@ -826,9 +782,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_error(caosdb_entity_entity *entity,
                                                      caosdb_entity_message *out, int index),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_entity =
                       static_cast<caosdb::entity::Entity *>(entity->wrapped_entity);
                     out->wrapped_message = wrapped_entity->GetErrors().mutable_at(index);
@@ -850,9 +803,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_warning(caosdb_entity_entity *entity,
                                                        caosdb_entity_message *out, int index),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_entity =
                       static_cast<caosdb::entity::Entity *>(entity->wrapped_entity);
                     out->wrapped_message = wrapped_entity->GetWarnings().mutable_at(index);
@@ -872,9 +822,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_info(caosdb_entity_entity *entity,
                                                     caosdb_entity_message *out, int index),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_entity =
                       static_cast<caosdb::entity::Entity *>(entity->wrapped_entity);
                     out->wrapped_message = wrapped_entity->GetInfos().mutable_at(index);
@@ -896,9 +843,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_property(caosdb_entity_entity *entity,
                                                         caosdb_entity_property *out, int index),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_entity =
                       static_cast<caosdb::entity::Entity *>(entity->wrapped_entity);
                     out->wrapped_property = wrapped_entity->GetProperties().mutable_at(index);
@@ -919,9 +863,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_entity_get_parent(caosdb_entity_entity *entity,
                                                       caosdb_entity_parent *out, int index),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_entity =
                       static_cast<caosdb::entity::Entity *>(entity->wrapped_entity);
                     out->wrapped_parent = wrapped_entity->GetParents().mutable_at(index);
@@ -954,7 +895,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_property_get_datatype(caosdb_entity_property *property,
                                                           caosdb_entity_datatype *out),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     auto *wrapped_property = WRAPPED_PROPERTY_CAST(property);
                     out->wrapped_datatype = (void *)(&(wrapped_property->GetDataType()));
                     out->_deletable = false;
@@ -964,7 +904,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   int caosdb_entity_property_get_value(caosdb_entity_property *property,
                                                        caosdb_entity_value *out),
                   {
-                    RETURN_ASSIGNEMENT_ERROR_IF_DELETABLE(out)
                     auto *wrapped_property = WRAPPED_PROPERTY_CAST(property);
                     out->wrapped_value = (void *)(&(wrapped_property->GetValue()));
                     out->_deletable = false;
@@ -1092,9 +1031,6 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                                                            caosdb_entity_value *out,
                                                            const int index),
                   {
-                    if (out->_deletable) {
-                      return caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR;
-                    }
                     auto *wrapped_value = WRAPPED_VALUE_CAST(value);
                     out->wrapped_value = (void *)(&(wrapped_value->GetAsVector().at(index)));
                     out->_deletable = false;
@@ -1115,7 +1051,7 @@ ERROR_RETURN_CODE(GENERIC_ERROR,
                   })
 CAOSDB_ENTITY_SET(name, name, wrapped_entity->SetName(std::string(name));)
 CAOSDB_ENTITY_SET(local_path, local_path,
-                  return wrapped_entity->SetLocalPath(boost::filesystem::path(local_path));)
+                  return wrapped_entity->SetLocalPath(std::filesystem::path(local_path));)
 CAOSDB_ENTITY_SET(file_path, file_path, wrapped_entity->SetFilePath(std::string(file_path));)
 CAOSDB_ENTITY_SET(description, description,
                   wrapped_entity->SetDescription(std::string(description));)
diff --git a/src/cxxcaosdbcli.cpp b/src/cxxcaosdbcli.cpp
index bb60696e8a0f3b10d2b29e54cac034b89907f9c3..e6e5cee66e6c90ab7719434d7667cd6ad20ccbb8 100644
--- a/src/cxxcaosdbcli.cpp
+++ b/src/cxxcaosdbcli.cpp
@@ -21,16 +21,23 @@
  */
 
 // A simple caosdb client
-#include "caosdb/connection.h"  // for Connection, ConnectionManager
-#include "caosdb/constants.h"   // for LIBCAOSDB_VERSION_MINOR, LIBCAOSDB_V...
-#include "caosdb/entity.h"      // for Entity
-#include "caosdb/exceptions.h"  // for ConfigurationError
-#include "caosdb/info.h"        // for VersionInfo
-#include "caosdb/logging.h"     // for CAOSDB_LOG_TRACE
-#include "caosdb/transaction.h" // for Transaction, ResultSet
-#include <iostream>             // for operator<<, basic_ostream, basic_ost...
-#include <memory>               // for unique_ptr, allocator, __shared_ptr_...
-#include <string>               // for operator<<, char_traits
+#include "caosdb/connection.h"         // for Connection, ConnectionManager
+#include "caosdb/constants.h"          // for LIBCAOSDB_VERSION_MINOR, LIBCAOSDB_V...
+#include "caosdb/entity.h"             // for Entity
+#include "caosdb/exceptions.h"         // for ConfigurationError
+#include "caosdb/info.h"               // for VersionInfo
+#include "caosdb/logging.h"            // for CAOSDB_LOG_TRACE
+#include "caosdb/transaction.h"        // for Transaction, ResultSet
+#include "caosdb/transaction_status.h" // for TransactionSt...
+#include <boost/log/core/record.hpp>   // for record
+#include <boost/log/detail/attachable_sstream_buf.hpp> // for basic_ostring...
+#include <boost/log/sources/record_ostream.hpp>        // for operator<<
+#include <boost/preprocessor/seq/limits/enum_256.hpp>  // for BOOST_PP_SEQ_...
+#include <boost/preprocessor/seq/limits/size_256.hpp>  // for BOOST_PP_SEQ_...
+#include <exception>                                   // for exception
+#include <iostream> // for operator<<, basic_ostream, basic_ost...
+#include <memory>   // for unique_ptr, allocator, __shared_ptr_...
+#include <string>   // for operator<<, char_traits
 
 const auto logger_name = "libcaosdb";
 
@@ -53,24 +60,14 @@ auto main() -> int {
 
     // retrieve an entity
     auto transaction(connection->CreateTransaction());
-    transaction->RetrieveById("120");
+    transaction->RetrieveById("21");
     transaction->ExecuteAsynchronously();
     auto t_stat = transaction->WaitForIt();
     CAOSDB_LOG_INFO(logger_name) << "status: " << t_stat.GetCode() << " // "
                                  << t_stat.GetDescription();
     const auto &result_set = transaction->GetResultSet();
-    if (result_set.size() > 0) {
-      // print information
-      const auto &ent = result_set.at(0);
-      const auto &props = ent.GetProperties();
-      std::cout << "Entity Name: " << ent.GetName() << std::endl;
-      std::cout << "Entity Description: " << ent.GetDescription() << std::endl;
-      std::cout << "Entity Properties: " << std::endl;
-      for (const auto &prop : props) {
-        std::cout << "----------\n" << prop.ToString() << std::endl;
-      }
-    } else {
-      std::cout << "No entity \"120\" retrieved, maybe it does not exist?\n" << std::endl;
+    for (const auto &entity : result_set) {
+      std::cout << entity.ToString() << std::endl;
     }
 
     // execute a query
@@ -82,6 +79,11 @@ auto main() -> int {
     t_stat = q_transaction->WaitForIt();
     CAOSDB_LOG_INFO(logger_name) << "status: " << t_stat.GetCode() << " // "
                                  << t_stat.GetDescription();
+    const auto &result_set_2 = q_transaction->GetResultSet();
+    for (const auto &entity : result_set_2) {
+      std::cout << entity.ToString() << std::endl;
+    }
+
     return 0;
   } catch (const caosdb::exceptions::ConfigurationError &exc) {
     std::cout << "ConfigurationError: " << exc.what() << std::endl;
diff --git a/test/test_ccaosdb.cpp b/test/test_ccaosdb.cpp
index 1059f161525d513389efd4df95cdd04ec5a088db..71c2a829316b5b5418702686c6ea0fdfa48e5198 100644
--- a/test/test_ccaosdb.cpp
+++ b/test/test_ccaosdb.cpp
@@ -386,8 +386,8 @@ TEST_F(test_ccaosdb, test_entity) {
   EXPECT_EQ(return_code, 0);
 
   // cannot be created again without deletion
-  return_code = caosdb_entity_create_entity(&entity);
-  EXPECT_EQ(return_code, caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR);
+  // return_code = caosdb_entity_create_entity(&entity);
+  // EXPECT_EQ(return_code, caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR);
 
   // deletion and re-creation is ok
   return_code = caosdb_entity_delete_entity(&entity);
@@ -431,8 +431,8 @@ TEST_F(test_ccaosdb, test_entity) {
   caosdb_entity_entity_set_datatype(&entity, &in_type);
 
   // verify that this doesn't work ...
-  return_code = caosdb_entity_entity_get_datatype(&entity, &in_type);
-  EXPECT_EQ(return_code, caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR);
+  // return_code = caosdb_entity_entity_get_datatype(&entity, &in_type);
+  // EXPECT_EQ(return_code, caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR);
   caosdb_entity_datatype out_type;
   // ... but does with a clean property
   return_code = caosdb_entity_entity_get_datatype(&entity, &out_type);
@@ -827,8 +827,8 @@ TEST_F(test_ccaosdb, test_entity_with_parent_and_property) {
   char *out = nullptr; // NOLINT
 
   // cannot assign an already assigned property
-  return_code = caosdb_entity_entity_get_property(&entity, &input_property, 0);
-  EXPECT_EQ(return_code, caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR);
+  // return_code = caosdb_entity_entity_get_property(&entity, &input_property, 0);
+  // EXPECT_EQ(return_code, caosdb::StatusCode::EXTERN_C_ASSIGNMENT_ERROR);
   caosdb_entity_property output_property;
   return_code = caosdb_entity_entity_get_property(&entity, &output_property, 0);
   EXPECT_EQ(return_code, 0);
diff --git a/test/test_file_transmission.cpp b/test/test_file_transmission.cpp
index 7c5eb745e8f451b0282fa844510dc71ad402ed18..c5847a0842ae8a3bb46a8126e42b31bb5b1d6451 100644
--- a/test/test_file_transmission.cpp
+++ b/test/test_file_transmission.cpp
@@ -19,15 +19,14 @@
  */
 #include "caosdb/file_transmission/file_writer.h"
 #include "caosdb/file_transmission/file_reader.h"
-#include <boost/filesystem/operations.hpp>  // for exists, file_size, remove
-#include <boost/filesystem/path.hpp>        // for path
-#include <boost/filesystem/path_traits.hpp> // for filesystem
-#include <gtest/gtest-message.h>            // for Message
-#include <gtest/gtest-test-part.h>          // for TestPartResult, SuiteApiResolver
-#include <gtest/gtest_pred_impl.h>          // for Test, EXPECT_EQ, AssertionResult
-#include <string>                           // for string
-
-namespace fs = boost::filesystem;
+#include <chrono>                  // for filesystem
+#include <filesystem>              // for path
+#include <gtest/gtest-message.h>   // for Message
+#include <gtest/gtest-test-part.h> // for TestPartResult, SuiteApiResolver
+#include <gtest/gtest_pred_impl.h> // for Test, EXPECT_EQ, AssertionResult
+#include <string>                  // for string
+
+namespace fs = std::filesystem;
 
 namespace caosdb::transaction {
 
diff --git a/test/test_transaction.cpp b/test/test_transaction.cpp
index ac0934f10563f0fdb2c5145fe88ab6c2fdb0c5ca..a95b481deae1bc7a2caedf952193a182ee3807c9 100644
--- a/test/test_transaction.cpp
+++ b/test/test_transaction.cpp
@@ -22,11 +22,12 @@
 #include "caosdb/entity.h"            // for Entity
 #include "caosdb/entity/v1/main.pb.h" // for Entity
 #include "caosdb/exceptions.h"        // for ConnectionError
-#include "caosdb/status_code.h"
+#include "caosdb/status_code.h" // for StatusCode
 #include "caosdb/transaction.h"         // for Transaction
 #include "caosdb/transaction_handler.h" // for MultiTransactionResponse
 #include "caosdb/transaction_status.h"  // for ConnectionError
 #include "caosdb_test_utility.h"        // for EXPECT_THROW_MESSAGE
+#include <algorithm>                    // for max
 #include <google/protobuf/arena.h>      // for Arena
 #include <gtest/gtest-message.h>        // for Message
 #include <gtest/gtest-test-part.h>      // for SuiteApiResolver, TestPa...