--- /dev/null
+diff -urNp tar-1.23-orig/src/tar.c tar-1.23/src/tar.c
+--- tar-1.23-orig/src/tar.c 2010-06-01 13:55:03.792173060 +0200
++++ tar-1.23/src/tar.c 2010-06-01 14:01:40.494172986 +0200
+@@ -1911,6 +1911,10 @@ parse_opt (int key, char *arg, struct ar
+ _("Invalid number")));
+ }
+ break;
++
++ case OLD_ARCHIVE_OPTION:
++ set_archive_format ("v7");
++ break;
+
+ case OVERWRITE_DIR_OPTION:
+ old_files_option = DEFAULT_OLD_FILES;