diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d6257e..e34b67a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.23)
+cmake_minimum_required(VERSION 3.9)
 
 # Make sure the user doesn't play dirty with symlinks
 get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" REALPATH)
@@ -14,87 +14,18 @@ if(${srcdir} STREQUAL ${bindir})
 endif()
 
 project(odm CXX)
-
-if(NOT CMAKE_BUILD_TYPE)
- set(CMAKE_BUILD_TYPE Release CACHE STRING "Choose the type of build, options are: Debug Release RelWithDebInfo MinSizeRel" FORCE)
-endif()
-
-set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/modules/" CACHE INTERNAL "Location of our custom CMake modules." FORCE)
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ON)
 
 include_directories(include)
+add_compile_options(-Wall)
 
-# Checking compiler options
-set(default_options -Wall)
-set(linker_options -Wall)
-include(CheckCXXCompilerFlag)
-set(saved_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-# C++20 is required
-CHECK_CXX_COMPILER_FLAG(-std=c++20 COMPILER_SUPPORTS_CXX20)
-if(COMPILER_SUPPORTS_CXX20)
- set(default_options ${default_options} -std=c++20)
-else()
-  message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no C++20 support. Please use a different C++ compiler.")
-endif()
-# OpenMP is required
-CHECK_CXX_COMPILER_FLAG(-fopenmp COMPILER_SUPPORTS_OPENMP)
-if(COMPILER_SUPPORTS_OPENMP)
- set(default_options ${default_options} -fopenmp)
- set(linker_options ${linker_options} -fopenmp)
-else()
-  message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no OpenMP support. Please use a different C++ compiler.")
-endif()
-# Link time optimization check
-set(CMAKE_REQUIRED_FLAGS -flto=auto)
-CHECK_CXX_COMPILER_FLAG(-flto=auto COMPILER_SUPPORTS_FLTO)
-if(COMPILER_SUPPORTS_FLTO AND NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
- set(default_options ${default_options} -flto=auto)
- set(linker_options ${linker_options} -flto=auto)
-endif()
-unset(CMAKE_REQUIRED_FLAGS)
-# Clang can use lto only with gold linker
-if(NOT COMPILER_SUPPORTS_FLTO)
- set(CMAKE_REQUIRED_FLAGS -flto\ -fuse-ld=gold)
- CHECK_CXX_COMPILER_FLAG(-flto\ -fuse-ld=gold COMPILER_SUPPORTS_FLTO_GOLD)
- if(COMPILER_SUPPORTS_FLTO_GOLD AND NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
-  set(default_options ${default_options} -flto)
-  set(linker_options ${linker_options} -flto\ -fuse-ld=gold)
- endif()
- unset(CMAKE_REQUIRED_FLAGS)
-endif()
 # Dwarf-4 support check
-set(CMAKE_REQUIRED_FLAGS -gdwarf-4)
+include(CheckCXXCompilerFlag)
 CHECK_CXX_COMPILER_FLAG(-gdwarf-4 COMPILER_SUPPORTS_DWARF4)
 if(COMPILER_SUPPORTS_DWARF4 AND (CMAKE_BUILD_TYPE STREQUAL "Debug" OR CMAKE_BUILD_TYPE STREQUAL "RelWithDebInfo"))
- set(default_options ${default_options} -gdwarf-4)
- set(linker_options ${linker_options} -gdwarf-4)
-endif()
-unset(CMAKE_REQUIRED_FLAGS)
-# -ipo flag check (Intel compiler link time optimization)
-set(CMAKE_REQUIRED_FLAGS -ipo)
-CHECK_CXX_COMPILER_FLAG(-ipo COMPILER_SUPPORTS_IPO)
-if(COMPILER_SUPPORTS_IPO AND NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
- set(default_options ${default_options} -ipo)
- set(linker_options ${linker_options} -ipo)
-endif()
-unset(CMAKE_REQUIRED_FLAGS)
-# Default hidden visibility check
-set(CMAKE_REQUIRED_FLAGS -fvisibility=hidden)
-CHECK_CXX_COMPILER_FLAG(-fvisibility=hidden COMPILER_SUPPORTS_HIDDEN)
-if(COMPILER_SUPPORTS_HIDDEN)
- set(default_options ${default_options} -fvisibility=hidden)
- set(linker_options ${linker_options} -fvisibility=hidden)
-endif()
-unset(CMAKE_REQUIRED_FLAGS)
-# Export dynamic. Required as modules mast call functions from main programm
-set(CMAKE_REQUIRED_FLAGS -Wl,--export-dynamic)
-CHECK_CXX_COMPILER_FLAG(-Wl,--export-dynamic COMPILER_SUPPORTS_EXPORTDYNAMIC)
-if(COMPILER_SUPPORTS_EXPORTDYNAMIC)
- set(linker_options ${linker_options} -Wl,--export-dynamic)
-else()
- message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no support of --export-dynamic. Please use a different C++ compiler.")
+ add_compile_options(-gdwarf-4)
 endif()
-unset(CMAKE_REQUIRED_FLAGS)
-add_compile_options(${default_options})
-set(CMAKE_REQUIRED_FLAGS ${saved_CMAKE_REQUIRED_FLAGS})
 
 add_subdirectory(src)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d0bd852..aa6a96d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,11 +1,13 @@
 set(EXENAME odm)
 
 find_library(netcdf netcdf REQUIRED)
+find_package(OpenMP REQUIRED)
+set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
 
 include_directories(../michlib/michlib)
 
 file(GLOB srcs *.cpp)
 add_executable(${EXENAME} ${srcs})
-target_link_libraries(${EXENAME} ${linker_options} ${netcdf})
+target_link_libraries(${EXENAME} ${linker_options} ${netcdf} OpenMP::OpenMP_CXX)
 set_target_properties(${EXENAME} PROPERTIES POSITION_INDEPENDENT_CODE ON)
 install(TARGETS ${EXENAME})