diff --git a/src/saveload/saveload.h b/src/saveload/saveload.h
index f498fa2839..e14d297b75 100644
--- a/src/saveload/saveload.h
+++ b/src/saveload/saveload.h
@@ -399,6 +399,8 @@ enum SaveLoadVersion : uint16_t {
 
 	SLV_EXTENDED_DEPOTS,                    ///< 321  PR#8480 Extended depots for rail, road and water transport.
 
+	SLV_PATCHED = UINT16_MAX - 6,           ///< Make it difficult to load any savegame made with
+			// this patched version in any other version of OpenTTD (unless it uses the same saveload version trick).
 	SL_MAX_VERSION,                         ///< Highest possible saveload version
 };