diff --git a/CMakeLists.txt b/CMakeLists.txt
index 903133a1..82466481 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,17 +7,17 @@ set(FSFW_REVISION 0)
 # Add the cmake folder so the FindSphinx module is found
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
 
-set(FSFW_ETL_LIB_MAJOR_VERSION 20 CACHE
+set(FSFW_ETL_LIB_MAJOR_VERSION 20 CACHE STRING
     "ETL library major version requirement"
 )
-set(FSFW_ETL_LIB_VERSION ${FSFW_ETL_LIB_MAJOR_VERSION}.26.0 CACHE
+set(FSFW_ETL_LIB_VERSION ${FSFW_ETL_LIB_MAJOR_VERSION}.26.0 CACHE STRING
     "ETL library exact version requirement"
 )
 
-set(FSFW_CATCH2_LIB_MAJOR_VERSION 3 CACHE
+set(FSFW_CATCH2_LIB_MAJOR_VERSION 3 CACHE STRING
     "Catch2 library major version requirement"
 )
-set(FSFW_CATCH2_LIB_VERSION v${FSFW_CATCH2_LIB_MAJOR_VERSION}.0.0-preview4 CACHE
+set(FSFW_CATCH2_LIB_VERSION v${FSFW_CATCH2_LIB_MAJOR_VERSION}.0.0-preview4 CACHE STRING
     "Catch2 library exact version requirement"
 )