diff --git a/CMakeLists.txt b/CMakeLists.txt
index a58d82bb7b..e151c0d547 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,8 +11,8 @@ option(RUN_REGRESS_TEST "run regression tests on build" OFF)
 option(RUN_SYSTEM_TEST "run system tests on build" OFF)
 option(RUN_MEMORY_TEST "run cxxtest testing with ASAN ON" ON)
 
-set(DEFAULT_PYTHON_VERSION "3" CACHE STRING "Default Python version 2/3")
-set(PYTHON_VERSIONS_SUPPORTED 2 3)
+set(DEFAULT_PYTHON_VERSION "3" CACHE STRING "Default Python version 3")
+set(PYTHON_VERSIONS_SUPPORTED 3)
 list(FIND PYTHON_VERSIONS_SUPPORTED ${DEFAULT_PYTHON_VERSION} index)
 if(index EQUAL -1)
     message(FATAL_ERROR "python version must be one of ${PYTHON_VERSIONS_SUPPORTED}")