diff --git a/src/adapters/ExplicitModelAdapter.cpp b/src/adapters/ExplicitModelAdapter.cpp
index 9c20eca69..3963ec81b 100644
--- a/src/adapters/ExplicitModelAdapter.cpp
+++ b/src/adapters/ExplicitModelAdapter.cpp
@@ -27,47 +27,7 @@
 extern log4cplus::Logger logger;
 
 bool ExplicitModelAdapterOptionsRegistered = storm::settings::Settings::registerNewModule([] (storm::settings::Settings* instance) -> bool {
-	instance->addOption(storm::settings::OptionBuilder("ExplicitModelAdapter", "constants", "", "Specifies the constant replacements to use in Explicit Models").addArgument(storm::settings::ArgumentBuilder::createStringArgument("constantString", "A comma separated list of constants and their value, e.g. a=1,b=2,c=3").addValidationFunctionString(
-		[] (std::string const s, std::string& errorMessageTarget) -> bool {
-			// since regex is not yet implemented in gccs C++11, we have to check by hand
-			std::vector<std::string> constants;
-			// split for single assignment expressions
-			boost::split(constants, s, boost::is_any_of(","));
-			for (auto it = constants.cbegin(); it != constants.cend(); ++it) {
-				std::vector<std::string> constant;
-				boost::split(constant, *it, boost::is_any_of("="));
-				if (constant.size() != 2) {
-					std::ostringstream stream;
-					stream << "Expected one \"=\" in constant definition: \"" << *it << "\"" << std::endl; 
-					errorMessageTarget.append(stream.str());
-					return false;
-				}
-				// Constant Name check
-				bool error = false;
-				std::for_each(constant.at(0).cbegin(), constant.at(0).cend(), [&error, &errorMessageTarget] (const std::string::value_type value) -> void {
-					if (!(('a' <= value && value <= 'z') || ('A' <= value && value <= 'Z') || ('0' <= value && value <= '9'))) {
-						std::ostringstream stream;
-						stream << "Illegal character in constant name: \"" << value << "\"" << std::endl; 
-						errorMessageTarget.append(stream.str());
-						error = true;
-					}
-				});
-				// Value Check
-				std::for_each(constant.at(1).cbegin(), constant.at(1).cend(), [&error, &errorMessageTarget] (const std::string::value_type value) -> void {
-					if (!(('a' <= value && value <= 'z') || ('A' <= value && value <= 'Z') || ('0' <= value && value <= '9'))) {
-						std::ostringstream stream;
-						stream << "Illegal character in constant value: \"" << value << "\"" << std::endl; 
-						errorMessageTarget.append(stream.str());
-						error = true;
-					}
-				});
-				if (error) {
-					return false;
-				}
-			}
-
-			return true;
-	}).setDefaultValueString("").build()).build());
+	instance->addOption(storm::settings::OptionBuilder("ExplicitModelAdapter", "constants", "", "Specifies the constant replacements to use in Explicit Models").addArgument(storm::settings::ArgumentBuilder::createStringArgument("constantString", "A comma separated list of constants and their value, e.g. a=1,b=2,c=3").setDefaultValueString("").build()).build());
 	return true;
 });