diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1e4e1b6..c919063 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 4.1.1)
+cmake_minimum_required(VERSION 3.5)
 
 project(
     cppli
@@ -7,7 +7,7 @@ project(
     LANGUAGES CXX
 )
 
-set(CMAKE_CXX_STANDARD 23)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
@@ -31,7 +31,7 @@ target_include_directories(
         $<INSTALL_INTERFACE:include>
 )
 
-target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_23)
+target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_20)
 
 #if(MSVC)
 #    target_compile_options(${PROJECT_NAME} PRIVATE /W4 /WX)
@@ -78,7 +78,7 @@ if(CPPLI_BUILD_TESTS)
         PRIVATE ${PROJECT_NAME} Catch2::Catch2WithMain
     )
 
-    target_compile_features(cppli_tests PRIVATE cxx_std_23)
+    target_compile_features(cppli_tests PRIVATE cxx_std_20)
 
     include(CTest)
     include(Catch)
diff --git a/src/cppli_types.cpp b/src/cppli_types.cpp
index 91f17c3..d8f4ba0 100644
--- a/src/cppli_types.cpp
+++ b/src/cppli_types.cpp
@@ -1,57 +1,102 @@
-#include <charconv>
 #include <cppli_error.hpp>
 #include <cppli_types.hpp>
 #include <string>
 #include <system_error>
 
+#if __cpp_lib_charconv >= 201606L && !defined(__GNUC__) || __GNUC__ >= 8
+    #define USE_FROM_CHARS
+#endif
+
+#if defined(USE_FROM_CHARS)
+    #include <charconv>
+#else
+    #include <sstream>
+#endif
+
 namespace cli {
-	Result<int> ValueConverter<int>::from_string(std::string_view str) {
-		int value{};
-		auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value);
+#ifdef USE_FROM_CHARS
+    Result<int> ValueConverter<int>::from_string(std::string_view str) {
+        int value{};
+        auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value);
+
+        if (ec == std::errc()) {
+            return Result<int>::ok(value);
+        }
 
-		if (ec == std::errc()) {
-			return Result<int>::ok(value);
-		}
+        if (ec == std::errc::invalid_argument) {
+            return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Invalid integer format"));
+        }
 
-		if (ec == std::errc::invalid_argument) {
-			return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Invalid integer format"));
-		}
+        if (ec == std::errc::result_out_of_range) {
+            return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Integer out of range"));
+        }
 
-		if (ec == std::errc::result_out_of_range) {
-			return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Integer out of range"));
-		}
+        return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Unknown conversion error"));
+    }
 
-		return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Unknown conversion error"));
-	}
+    Result<double> ValueConverter<double>::from_string(std::string_view str) {
+        double value{};
+        auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value);
 
-	Result<double> ValueConverter<double>::from_string(std::string_view str) {
-		double value{};
-		auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value);
+        if (ec == std::errc()) {
+            return Result<double>::ok(value);
+        }
 
-		if (ec == std::errc()) {
-			return Result<double>::ok(value);
-		}
+        if (ec == std::errc::invalid_argument) {
+            return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Invalid floating-point format"));
+        }
 
-		if (ec == std::errc::invalid_argument) {
-			return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Invalid floating-point format"));
-		}
+        if (ec == std::errc::result_out_of_range) {
+            return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Floating-point out of range"));
+        }
 
-		if (ec == std::errc::result_out_of_range) {
-			return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Floating-point out of range"));
-		}
+        return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Unknown conversion error"));
+    }
+#else
+    Result<int> ValueConverter<int>::from_string(std::string_view str) {
+        try {
+            std::string str_copy(str);
+            std::istringstream iss(str_copy);
+            int value{};
+            iss >> value;
+            
+            if (iss.fail() || !iss.eof()) {
+                return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Invalid integer format"));
+            }
+            
+            return Result<int>::ok(value);
+        } catch (const std::exception&) {
+            return Result<int>::err(Error(ErrorCode::InvalidFlagValue, "Invalid integer format"));
+        }
+    }
 
-		return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Unknown conversion error"));
-	}
+    Result<double> ValueConverter<double>::from_string(std::string_view str) {
+        try {
+            std::string str_copy(str);
+            std::istringstream iss(str_copy);
+            double value{};
+            iss >> value;
+            
+            if (iss.fail() || !iss.eof()) {
+                return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Invalid floating-point format"));
+            }
+            
+            return Result<double>::ok(value);
+        } catch (const std::exception&) {
+            return Result<double>::err(Error(ErrorCode::InvalidFlagValue, "Invalid floating-point format"));
+        }
+    }
+#endif
 
-	Result<bool> ValueConverter<bool>::from_string(std::string_view str) {
-		if (str == "true" || str == "1" || str == "yes" || str == "on") {
-			return Result<bool>::ok(true);
-		}
+    Result<bool> ValueConverter<bool>::from_string(std::string_view str) {
+        if (str == "true" || str == "1" || str == "yes" || str == "on") {
+            return Result<bool>::ok(true);
+        }
 
-		if (str == "false" || str == "0" || str == "no" || str == "off") {
-			return Result<bool>::ok(false);
-		}
+        if (str == "false" || str == "0" || str == "no" || str == "off") {
+            return Result<bool>::ok(false);
+        }
 
-		return Result<bool>::err(Error(ErrorCode::InvalidFlagValue, "Invalid boolean value (expected: true/false, 1/0, yes/no, on/off)"));
-	}
-}// namespace cli
+        return Result<bool>::err(Error(ErrorCode::InvalidFlagValue, "Invalid boolean value (expected: true/false, 1/0, yes/no, on/off)"));
+    }
+} // namespace cli