diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6abcb15c..b8d69d68 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,9 +1,9 @@
 project (Tapkee  LANGUAGES CXX)
 
-cmake_minimum_required (VERSION 3.8)
+cmake_minimum_required (VERSION 3.5.1)
 
 # set paths
-set (CMAKE_CXX_STANDARD 17)
+set (CMAKE_CXX_STANDARD 14)
 set (TAPKEE_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/include")
 set (TAPKEE_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/src")
 set (TAPKEE_TESTS_DIR "${CMAKE_CURRENT_SOURCE_DIR}/test/unit")
diff --git a/include/tapkee/methods.hpp b/include/tapkee/methods.hpp
index dfefd8a3..f5cb50e2 100644
--- a/include/tapkee/methods.hpp
+++ b/include/tapkee/methods.hpp
@@ -161,7 +161,7 @@ class ImplementationBase
 		case X:																					\
 		{																						\
 			timed_context tctx__("[+] embedding with " # X);									\
-			if constexpr (																		\
+			if (																				\
 				((!MethodTraits<X>::needs_kernel)   || (!is_dummy<KernelCallback>::value))   &&	\
 				((!MethodTraits<X>::needs_distance) || (!is_dummy<DistanceCallback>::value)) &&	\
 				((!MethodTraits<X>::needs_features) || (!is_dummy<FeaturesCallback>::value))	\