The fsync_lock_unlock.js test executes the transitionFromDedicatedConfigServer command (unavailable in v6.0 and below) which causes the test to fail in mixed version testing of binaries that include v6.0 and v7.0. Fixing the entry in the backports_required_for_multiversion_tests.yml to have a different ticket number (the one which introduced the command) than the one in v6.0, will ensure that the sharding_last_lts_mongos_and_mixed_shards test suite does not allow the testing of v7.0 and v6.0 binaries.