diff --git a/config.lib b/config.lib
--- a/config.lib
+++ b/config.lib
@@ -633,10 +633,23 @@ check_params() {
 			revision="`cat $ROOT_DIR/version`"
 
 			log 1 "checking revision... $revision"
+		elif [ -d "$ROOT_DIR/.svn" ] && [ -n "`svn help`" ]; then
+			revision=""
+			log 1 "checking revision... svn detection"
+		elif [ -d "$ROOT_DIR/.git" ] && [ -n "`git help`" ]; then
+			revision=""
+			log 1 "checking revision... git detection"
 		else
 			revision=""
+			log 1 "checking revision... no detection"
+			log 1 "WARNING: there is no means to determine the version."
+			log 1 "WARNING: please use a subversion or git checkout of OpenTTD."
+			log 1 "WARNING: this version will be allowed by all game servers,"
+			log 1 "WARNING: but you will be kicked from all incompatible"
+			log 1 "WARNING: servers as you will desync."
+			log 1 "WARNING: USE WITH CAUTION!"
 
-			log 1 "checking revision... svn detection"
+			sleep 5
 		fi
 	fi
 }