we tested chaos with 4.26 preview version(was behaving weird) but epic did not include it in the actual 4.26 release, you need to build from source to be able to use it. there seems to be no need for any api change on our side so when chaos is ready we hope to be able to just use it right away. in theory chaos will change nothing(physics wise) for fgear but it seems to be the key to proper client prediction for replication.
we will release another maintenance build these days and we will experiment on a client authoritative replication option for 1.5 version. we might also recheck the status of chaos in the meantime.