diff --git a/src/base_media_base.h b/src/base_media_base.h
--- a/src/base_media_base.h
+++ b/src/base_media_base.h
@@ -59,6 +59,7 @@ struct BaseSet {
 	TranslatedStrings description; ///< Description of the base set
 	uint32 shortname;              ///< Four letter short variant of the name
 	uint32 version;                ///< The version of this base set
+	bool fallback;                 ///< This set is a fallback set, i.e. it should be used only as last resort
 
 	MD5File files[NUM_FILES];      ///< All files part of this set
 	uint found_files;              ///< Number of the files that could be found