diff --git a/Makefile b/Makefile
index 6419417f1f21ec4cf68ecf789368fdf663449eab..f3034bac3a2664b01122ea7a4b193f9b7d0afbf8 100644
--- a/Makefile
+++ b/Makefile
@@ -35,6 +35,14 @@ ifneq ($(GLUON_BRANCH),)
   GLUON_AUTOUPDATER_ENABLED ?= 1
 endif
 
+ifneq ($(GLUON_FEATURES)$(GLUON_FEATURES_standard)$(GLUON_FEATURES_tiny),)
+  $(error *** Warning: GLUON_FEATURES has been obsolete, please use the image-customization file instead.)
+endif
+
+ifneq ($(GLUON_SITE_PACKAGES)$(GLUON_SITE_PACKAGES_standard)$(GLUON_SITE_PACKAGES_tiny),)
+  $(error *** Warning: GLUON_SITE_PACKAGES has been obsolete, please use the image-customization file instead.)
+endif
+
 GLUON_AUTOUPDATER_ENABLED ?= 0
 
 # initialize (possibly already user set) directory variables