diff --git a/CMakeLists.txt b/CMakeLists.txt
index 85a5383bde8..e69f5558320 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1102,7 +1102,7 @@ if (WITH_CORE AND WITH_BINDINGS)
   include(SIPMacros)
 
   set(SIP_INCLUDES ${PYQT_SIP_DIR} ${CMAKE_SOURCE_DIR}/python)
-  set(SIP_CONCAT_PARTS 30)
+  set(SIP_CONCAT_PARTS 25)
 
   if (NOT BINDINGS_GLOBAL_INSTALL)
     set(Python_SITEARCH ${QGIS_DATA_DIR}/python)