diff --git a/.cmake-format b/.cmake-format
index 814ae81..757f231 100644
--- a/.cmake-format
+++ b/.cmake-format
@@ -1,6 +1,6 @@
 format:
   tab_size: 4
-  line_width: 80
+  line_width: 97
   dangle_parens: true
 
 markup:
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 0bdbfe6..24522e0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -28,7 +28,6 @@ default:
     - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
     - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
 
-
 stages:          # List of stages for jobs, and their order of execution
   - build
   - test
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 515e153..4f20c26 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,8 +1,8 @@
-cmake_minimum_required(VERSION 3.21...3.27)
+cmake_minimum_required(VERSION 3.21...3.28)
 
 # Not ideal to use this global variable, but necessary to make sure that tooling and projects use
 # the same version
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 17)
 
 # strongly encouraged to enable this globally to avoid conflicts between -Wpedantic being enabled
 # and -std=c++20 and -std=gnu++20 for example when compiling with PCH enabled
@@ -26,28 +26,30 @@ include(GNUInstallDirs)
 # search required packages and libs
 #---------------------------------------------------------------------------------------
 
-find_package(
-    Boost 1.71 CONFIG
-    COMPONENTS filesystem
-    REQUIRED
-)
-
-find_package(Threads REQUIRED)
+# find_package(
+#     Boost 1.81 CONFIG
+#     COMPONENTS filesystem asio headers
+#     REQUIRED
+# )
 
 # ---- Add other dependencies via CPM ----
 # see https://github.com/cpm-cmake/CPM.cmake for more info
 
 include(cmake/CPM.cmake)
 
+option(BUILD_SHARED_LIBS "Build shared libraries" YES)
+set(BOOST_INCLUDE_LIBRARIES filesystem asio headers)
+CPMAddPackage("gh:ClausKlein/boost-cmake@1.81.0-rc3")
+
 # PackageProject.cmake will be used to make our target installable
-CPMAddPackage("gh:TheLartians/PackageProject.cmake@1.11.0")
+# XXX done with boost-cmake! CPMAddPackage("gh:TheLartians/PackageProject.cmake@1.11.0")
 
 # see https://github.com/aminya/project_options for more info
 CPMAddPackage("gh:aminya/project_options@0.32.1")
 # XXX list(APPEND CMAKE_MODULE_PATH ${project_options_SOURCE_DIR})
 
 add_library(
-    tftpd STATIC
+    tftpd # FIXME(CK) STATIC
     async_tftpd_server.cpp
     async_tftpd_server.hpp
     tftpd.hpp
@@ -56,9 +58,8 @@ add_library(
     tftp_subs.cpp
     tftp/tftpsubs.h
 )
-target_link_libraries(
-    ${PROJECT_NAME} PUBLIC Boost::filesystem Boost::headers Threads::Threads
-)
+list(TRANSFORM BOOST_INCLUDE_LIBRARIES PREPEND Boost:: OUTPUT_VARIABLE BOOST_TARGETS)
+target_link_libraries(${PROJECT_NAME} PUBLIC ${BOOST_TARGETS})
 target_compile_definitions(${PROJECT_NAME} PUBLIC BOOST_ASIO_NO_DEPRECATED)
 target_include_directories(
     ${PROJECT_NAME} PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
@@ -81,11 +82,9 @@ if(PROJECT_IS_TOP_LEVEL AND CMAKE_BUILD_TYPE STREQUAL "Debug")
         # ENABLE_INCLUDE_WHAT_YOU_USE
     )
 
-    # FIXME: should be PRIVATE! CK
     target_link_libraries(
-        ${PROJECT_NAME}
-        PUBLIC $<BUILD_INTERFACE:${PROJECT_NAME}_project_warnings>
-               $<BUILD_INTERFACE:${PROJECT_NAME}_project_options>
+        ${PROJECT_NAME} PUBLIC $<BUILD_INTERFACE:${PROJECT_NAME}_project_warnings>
+                               $<BUILD_INTERFACE:${PROJECT_NAME}_project_options>
     )
 else()
     include(cmake/WarningsAsErrors.cmake)
@@ -106,12 +105,25 @@ if(NOT CMAKE_SKIP_INSTALL_RULES)
         # EXPORT_HEADER ${EXPORT_HEADER_LOCATION}
         COMPATIBILITY SameMajorVersion
         DISABLE_VERSION_SUFFIX YES
-        DEPENDENCIES "boost 1.71"
+        DEPENDENCIES "Boost 1.81"
     )
     # NOTE: implicit done! add_library(tftpd::tftpd ALIAS tftpd)
-    install(FILES async_tftpd_server.hpp
-            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-    )
+    install(FILES async_tftpd_server.hpp DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+
+    if(BUILD_SHARED_LIBS)
+        install(IMPORTED_RUNTIME_ARTIFACTS ${PROJECT_NAME} RUNTIME_DEPENDENCY_SET
+                _dependency_set
+        )
+        install(
+            RUNTIME_DEPENDENCY_SET
+            _dependency_set
+            POST_EXCLUDE_REGEXES
+            "${CMAKE_INSTALL_PREFIX}/lib"
+            RUNTIME
+            DESTINATION
+            lib
+        )
+    endif()
 
     include(CPack)
 endif()
diff --git a/CMakePresets.json b/CMakePresets.json
index 43509bc..6f09c59 100644
--- a/CMakePresets.json
+++ b/CMakePresets.json
@@ -19,9 +19,9 @@
           "value": "${sourceDir}/stagedir"
         },
         "CMAKE_CXX_STANDARD": "20",
-        "CMAKE_BUILD_TYPE": "Debug",
+        "CMAKE_BUILD_TYPE": "Release",
         "CMAKE_DEBUG_POSTFIX": "D",
-        "BUILD_SHARED_LIBS": "NO"
+        "BUILD_SHARED_LIBS": true
       },
       "environment": {
         "CMAKE_EXPORT_COMPILE_COMMANDS": "YES",
diff --git a/cmake/CPM.cmake b/cmake/CPM.cmake
index ff9d31c..0abb277 100644
--- a/cmake/CPM.cmake
+++ b/cmake/CPM.cmake
@@ -1,17 +1,11 @@
-set(CPM_DOWNLOAD_VERSION 0.37.0)
+set(CPM_DOWNLOAD_VERSION 0.38.7)
 
 if(CPM_SOURCE_CACHE)
-    set(_CPM_DOWNLOAD_LOCATION
-        "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake"
-    )
+    set(_CPM_DOWNLOAD_LOCATION "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
 elseif(DEFINED ENV{CPM_SOURCE_CACHE})
-    set(_CPM_DOWNLOAD_LOCATION
-        "$ENV{CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake"
-    )
+    set(_CPM_DOWNLOAD_LOCATION "$ENV{CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
 else()
-    set(_CPM_DOWNLOAD_LOCATION
-        "${CMAKE_BINARY_DIR}/cmake/CPM_${CPM_DOWNLOAD_VERSION}.cmake"
-    )
+    set(_CPM_DOWNLOAD_LOCATION "${CMAKE_BINARY_DIR}/cmake/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
 endif()
 
 set(CPM_DOWNLOAD_LOCATION
diff --git a/cmake/WarningsAsErrors.cmake b/cmake/WarningsAsErrors.cmake
index 3776fd5..b3881b4 100644
--- a/cmake/WarningsAsErrors.cmake
+++ b/cmake/WarningsAsErrors.cmake
@@ -1,18 +1,10 @@
-if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_SIMULATE_ID MATCHES
-                                             "MSVC"
-)
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
     target_compile_options(${PROJECT_NAME} PRIVATE /W4 /WX)
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
-    target_compile_options(
-        ${PROJECT_NAME} PRIVATE -Wall -Wextra -Wpedantic -Werror -Wshadow
-    )
+    target_compile_options(${PROJECT_NAME} PRIVATE -Wall -Wextra -Wpedantic -Werror -Wshadow)
 
-    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION
-                                                  GREATER_EQUAL 10.0
-    )
-        target_compile_options(
-            ${PROJECT_NAME} PRIVATE -Wdeprecated-copy-dtor -Wnewline-eof
-        )
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION GREATER_EQUAL 10.0)
+        target_compile_options(${PROJECT_NAME} PRIVATE -Wdeprecated-copy-dtor -Wnewline-eof)
     endif()
 elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
     string(REGEX REPLACE " /W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
diff --git a/option_test.cpp b/option_test.cpp
index c82bd59..aa68000 100644
--- a/option_test.cpp
+++ b/option_test.cpp
@@ -41,7 +41,7 @@ int main()
                              "tsize\0"s
                              "12345678910\0"s};
         std::vector<char> msg(test1.begin(), test1.end());
-        msg.resize(PKTSIZE);
+        // TODO(CK): why? msg.resize(PKTSIZE);
         err = tftpd::tftp(msg, fp, path, ackbuf);
         std::cout << path << " segsize:" << tftpd::g_segsize << " tsize:" << tftpd::g_tsize
                   << " timeout: " << tftpd::g_timeout << std::endl;
diff --git a/test.sh b/test.sh
index c5c6f18..e387d25 100755
--- a/test.sh
+++ b/test.sh
@@ -1,6 +1,6 @@
 #!/bin/bash -uex
 
-# NOTE: not loger used: tftp-hpa 5.2
+# NOTE: not longer used: tftp-hpa 5.2
 # Usage: tftp [-4][-6][-v][-V][-l][-m mode][-w size][-B blocksize] [-R port:port] [host [port]] [-c command]
 #XXX TFTP="/usr/bin/tftp -v -4 127.0.0.1 1234 -m binary"
 
@@ -148,7 +148,7 @@ fi
 ##############################################
 # NOTE we start our an own client
 ##############################################
-# normal binary upload with dublicate ack's
+# normal binary upload with duplicate ack's
 # TODO: should not fail
 ## bin/tftpd_test 1234 &
 ## sleep 1
@@ -168,7 +168,7 @@ if test "${UNAME}" == "Linux"; then
     wait
 fi
 ##############################################
-echo "NOTE: absolut path upload must fail!"
+echo "NOTE: absolute path upload must fail!"
 dd if=bin/tftpd_test of=test32k.dat bs=1024 count=32
 bin/tftpd_test 1234 &
 sleep 1
@@ -194,7 +194,7 @@ sleep 1
 ${TFTP} --input=build.ninja --upload=./../build.ninja && exit 1
 wait
 
-# invalid absolut path upload must fail
+# invalid absolute path upload must fail
 bin/tftpd_test 1234 &
 sleep 1
 ${TFTP} --input=build.ninja --upload=//srv///tftp/build.ninja && exit 1
diff --git a/tftp/tftp.1 b/tftp/tftp.1
index 951f24b..170cd60 100644
--- a/tftp/tftp.1
+++ b/tftp/tftp.1
@@ -83,7 +83,7 @@ Note that the
 protocol, unlike the
 .Tn FTP
 protocol,
-does not maintain connections betwen transfers; thus, the
+does not maintain connections between transfers; thus, the
 .Cm connect
 command does not actually create a connection,
 but merely remembers what host is to be used for transfers.
diff --git a/tftpd.hpp b/tftpd.hpp
index c42c7eb..aad0ac7 100644
--- a/tftpd.hpp
+++ b/tftpd.hpp
@@ -358,7 +358,7 @@ class receiver : public server
         } while (false);
 
         // ===============================
-        // write the current data segement
+        // write the current data segment
         // ===============================
         size_t const seg_length = rxlen - TFTP_HEADER;
         ssize_t written = writeit(file_guard_.get(), &dp_, seg_length, false);
diff --git a/tftpd_options.cpp b/tftpd_options.cpp
index a8bf3af..4d155e5 100644
--- a/tftpd_options.cpp
+++ b/tftpd_options.cpp
@@ -171,7 +171,7 @@ static bool set_tsize(uintmax_t *vp)
     }
 
     if (sz == 0) {
-        sz = g_tsize; // only usefull for RRQ
+        sz = g_tsize; // only useful for RRQ
     } else {
         g_tsize = sz; // in case of WRQ
     }
diff --git a/tftpd_utils.cpp b/tftpd_utils.cpp
index 78b66dc..db06802 100644
--- a/tftpd_utils.cpp
+++ b/tftpd_utils.cpp
@@ -49,6 +49,7 @@ char copyright[] = "@(#) Copyright (c) 1983 Regents of the University of Califor
 #include <boost/algorithm/string/case_conv.hpp>
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/current_function.hpp>
+#include <boost/filesystem.hpp>
 
 #include <arpa/inet.h>
 #include <cstdlib>
@@ -57,9 +58,17 @@ char copyright[] = "@(#) Copyright (c) 1983 Regents of the University of Califor
 #include <string>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <syslog.h>
 #include <vector>
 
+#ifdef __APPLE__
+#    define syslog fprintf
+#    define LOG_NOTICE stdout
+#    define LOG_WARNING stdout
+#    define LOG_ERR stderr
+#else
+#    include <syslog.h>
+#endif
+
 namespace tftpd {
 extern const char *g_rootdir; // the only tftp root dir used!
 
@@ -80,7 +89,7 @@ constexpr bool suppress_error{false};
 // Change root directory on startup. This means the remote host does not need to pass along the directory as part of the
 // transfer, and may add security.
 constexpr bool secure_tftp{true};
-// Allow new files to be created. Normaly, tftpd will only allow upload of files that already exist.
+// Allow new files to be created. Normally, tftpd will only allow upload of files that already exist.
 constexpr bool allow_create{true};
 
 struct formats
@@ -100,8 +109,17 @@ static struct formats formats[] = { // XXX {"netascii", /* validate_access, send
  */
 int tftp(const std::vector<char> &rxbuffer, FILE *&file, std::string &file_path, std::vector<char> &optack)
 {
+    // see too async_tftpd_server.cpp
+    boost::filesystem::path const dir(*dirs);
+    (void)boost::filesystem::create_directory(dir);
+
+#ifndef __APPLE__
+    openlog("ftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
+#endif
+
     syslog(LOG_NOTICE, "%s(%lu)\n", BOOST_CURRENT_FUNCTION, rxbuffer.size());
     init_opt();
+    file = nullptr;
 
     assert(rxbuffer.size() >= TFTP_HEADER);