diff --git a/CMakeLists.txt b/CMakeLists.txt
index dfbaa3de..277bad21 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,7 +34,9 @@
 ##  The Future will (be) Positive. Всё будет хорошо.
 ##
 
-if(CMAKE_VERSION VERSION_LESS 3.12)
+if(CMAKE_VERSION VERSION_LESS 3.8.2)
+  cmake_minimum_required(VERSION 3.0.2)
+elseif(CMAKE_VERSION VERSION_LESS 3.12)
   cmake_minimum_required(VERSION 3.8.2)
 else()
   cmake_minimum_required(VERSION 3.12)
@@ -385,6 +387,8 @@ if(NOT DEFINED MDBX_CXX_STANDARD)
     set(MDBX_CXX_STANDARD 14)
   elseif(NOT HAS_CXX11 LESS 0)
     set(MDBX_CXX_STANDARD 11)
+  elseif(CXX_FALLBACK_GNU11 OR CXX_FALLBACK_11)
+    set(MDBX_CXX_STANDARD 11)
   else()
     set(MDBX_CXX_STANDARD 98)
   endif()
@@ -533,7 +537,7 @@ else()
   unset(MDBX_LINK_TOOLS_NONSTATIC CACHE)
 endif()
 
-if(CMAKE_CXX_COMPILER_LOADED AND MDBX_CXX_STANDARD GREATER_EQUAL 11 AND MDBX_CXX_STANDARD LESS 83)
+if(CMAKE_CXX_COMPILER_LOADED AND MDBX_CXX_STANDARD LESS 83 AND NOT MDBX_CXX_STANDARD LESS 11)
   if(NOT MDBX_AMALGAMATED_SOURCE)
     option(MDBX_ENABLE_TESTS "Build MDBX tests" ${BUILD_TESTING})
   endif()
@@ -639,7 +643,11 @@ macro(target_setup_options TARGET)
 endmacro()
 
 macro(libmdbx_setup_libs TARGET MODE)
-  target_link_libraries(${TARGET} ${MODE} Threads::Threads)
+  if(CMAKE_VERSION VERSION_LESS 3.1)
+    target_link_libraries(${TARGET} ${MODE} ${CMAKE_THREAD_LIBS_INIT})
+  else()
+    target_link_libraries(${TARGET} ${MODE} Threads::Threads)
+  endif()
   if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
     target_link_libraries(${TARGET} ${MODE} ntdll advapi32)
     if(MDBX_NTDLL_EXTRA_IMPLIB AND MDBX_WITHOUT_MSVC_CRT)
@@ -906,16 +914,16 @@ else()
   endif()
   if(CMAKE_C_COMPILER_ABI
       AND NOT (CMAKE_C_COMPILER_ABI MATCHES ".*${MDBX_BUILD_TARGET}.*" OR MDBX_BUILD_TARGET MATCHES ".*${CMAKE_C_COMPILER_ABI}.*"))
-    string(APPEND MDBX_BUILD_TARGET "-${CMAKE_C_COMPILER_ABI}")
+    string(CONCAT MDBX_BUILD_TARGET "${MDBX_BUILD_TARGET}-${CMAKE_C_COMPILER_ABI}")
   endif()
   if(CMAKE_C_PLATFORM_ID
       AND NOT (CMAKE_SYSTEM_NAME
         AND (CMAKE_C_PLATFORM_ID MATCHES ".*${CMAKE_SYSTEM_NAME}.*" OR CMAKE_SYSTEM_NAME MATCHES ".*${CMAKE_C_PLATFORM_ID}.*"))
       AND NOT (CMAKE_C_PLATFORM_ID MATCHES ".*${CMAKE_C_PLATFORM_ID}.*" OR MDBX_BUILD_TARGET MATCHES ".*${CMAKE_C_PLATFORM_ID}.*"))
-    string(APPEND MDBX_BUILD_TARGET "-${CMAKE_C_COMPILER_ABI}")
+    string(CONCAT MDBX_BUILD_TARGET "${MDBX_BUILD_TARGET}-${CMAKE_C_COMPILER_ABI}")
   endif()
   if(CMAKE_SYSTEM_NAME)
-    string(APPEND MDBX_BUILD_TARGET "-${CMAKE_SYSTEM_NAME}")
+    string(CONCAT MDBX_BUILD_TARGET "${MDBX_BUILD_TARGET}-${CMAKE_SYSTEM_NAME}")
   endif()
 endif()
 
diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake
index ef308fc2..78a31946 100644
--- a/cmake/compiler.cmake
+++ b/cmake/compiler.cmake
@@ -13,7 +13,9 @@
 ##  limitations under the License.
 ##
 
-if(CMAKE_VERSION VERSION_LESS 3.12)
+if(CMAKE_VERSION VERSION_LESS 3.8.2)
+  cmake_minimum_required(VERSION 3.0.2)
+elseif(CMAKE_VERSION VERSION_LESS 3.12)
   cmake_minimum_required(VERSION 3.8.2)
 else()
   cmake_minimum_required(VERSION 3.12)
@@ -958,12 +960,13 @@ endmacro(setup_compile_flags)
 macro(probe_libcxx_filesystem)
   if(CMAKE_CXX_COMPILER_LOADED AND NOT DEFINED LIBCXX_FILESYSTEM)
     list(FIND CMAKE_CXX_COMPILE_FEATURES cxx_std_11 HAS_CXX11)
-    if(NOT HAS_CXX11 LESS 0)
+    if(NOT HAS_CXX11 LESS 0 OR CXX_FALLBACK_GNU11 OR CXX_FALLBACK_11)
       include(CMakePushCheckState)
       include(CheckCXXSourceCompiles)
       cmake_push_check_state()
       set(stdfs_probe_save_libraries ${CMAKE_REQUIRED_LIBRARIES})
       set(stdfs_probe_save_flags ${CMAKE_REQUIRED_FLAGS})
+      set(stdfs_probe_flags ${CMAKE_REQUIRED_FLAGS})
       set(stdfs_probe_save_link_options ${CMAKE_REQUIRED_LINK_OPTIONS})
       unset(stdfs_probe_clear_cxx_standard)
       if(NOT DEFINED CMAKE_CXX_STANDARD)
@@ -974,18 +977,23 @@ macro(probe_libcxx_filesystem)
           set(CMAKE_CXX_STANDARD 17)
         elseif(NOT HAS_CXX14 LESS 0)
           set(CMAKE_CXX_STANDARD 14)
-        else()
+        elseif(NOT HAS_CXX11 LESS 0)
           set(CMAKE_CXX_STANDARD 11)
+        elseif(CXX_FALLBACK_GNU11)
+          set(stdfs_probe_flags ${stdfs_probe_flags} "-std=gnu++11")
+        else()
+          set(stdfs_probe_flags ${stdfs_probe_flags} "-std=c++11")
         endif()
         set(stdfs_probe_clear_cxx_standard ON)
       endif()
       if(CMAKE_COMPILER_IS_ELBRUSCXX AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 1.25.23)
         if(CMAKE_VERSION VERSION_LESS 3.14)
-          set(CMAKE_REQUIRED_FLAGS ${stdfs_probe_save_flags} "-Wl,--allow-multiple-definition")
+          set(stdfs_probe_flags ${stdfs_probe_flags} "-Wl,--allow-multiple-definition")
         else()
           set(CMAKE_REQUIRED_LINK_OPTIONS ${stdfs_probe_save_link_options} "-Wl,--allow-multiple-definition")
         endif()
       endif()
+      set(CMAKE_REQUIRED_FLAGS ${stdfs_probe_flags})
 
       set(stdfs_probe_code [[
         #if defined(__SIZEOF_INT128__) && !defined(__GLIBCXX_TYPE_INT_N_0) && defined(__clang__) && __clang_major__ < 4
@@ -1066,6 +1074,7 @@ macro(probe_libcxx_filesystem)
       unset(stdfs_probe_clear_cxx_standard)
       unset(stdfs_probe_save_link_options)
       unset(stdfs_probe_save_flags)
+      unset(stdfs_probe_flags)
       unset(stdfs_probe_save_libraries)
       unset(stdfs_probe_code)
       unset(stdfs_probe_rc)
diff --git a/cmake/profile.cmake b/cmake/profile.cmake
index 6fe9c821..c9b8bed4 100644
--- a/cmake/profile.cmake
+++ b/cmake/profile.cmake
@@ -13,7 +13,9 @@
 ##  limitations under the License.
 ##
 
-if(CMAKE_VERSION VERSION_LESS 3.12)
+if(CMAKE_VERSION VERSION_LESS 3.8.2)
+  cmake_minimum_required(VERSION 3.0.2)
+elseif(CMAKE_VERSION VERSION_LESS 3.12)
   cmake_minimum_required(VERSION 3.8.2)
 else()
   cmake_minimum_required(VERSION 3.12)
diff --git a/cmake/utils.cmake b/cmake/utils.cmake
index a461cc27..6a3315e1 100644
--- a/cmake/utils.cmake
+++ b/cmake/utils.cmake
@@ -13,7 +13,9 @@
 ##  limitations under the License.
 ##
 
-if(CMAKE_VERSION VERSION_LESS 3.12)
+if(CMAKE_VERSION VERSION_LESS 3.8.2)
+  cmake_minimum_required(VERSION 3.0.2)
+elseif(CMAKE_VERSION VERSION_LESS 3.12)
   cmake_minimum_required(VERSION 3.8.2)
 else()
   cmake_minimum_required(VERSION 3.12)
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 5e7066e1..f8fb1618 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -54,7 +54,11 @@ if(NOT MDBX_BUILD_CXX AND LIBCXX_FILESYSTEM)
   target_link_libraries(mdbx_test ${LIBCXX_FILESYSTEM})
 endif()
 
-target_link_libraries(mdbx_test ${TOOL_MDBX_LIB} ${LIB_MATH} ${CMAKE_THREAD_LIBS_INIT})
+if(CMAKE_VERSION VERSION_LESS 3.1)
+  target_link_libraries(mdbx_test ${TOOL_MDBX_LIB} ${LIB_MATH} ${CMAKE_THREAD_LIBS_INIT})
+else()
+  target_link_libraries(mdbx_test ${TOOL_MDBX_LIB} ${LIB_MATH} Threads::Threads)
+endif()
 if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
   target_link_libraries(mdbx_test winmm.lib)
 endif()