We discovered an ugly bug with our 18.104.22.168803 release and are removing it from downloads.
The bug comes from a fix we inadvertently pulled in from LL, to a fix a bug we don't yet have, which has created a pretty nasty visual bug with doors, wheels and other things that rotate.
Because of this we are temporarily removing our downloads of 4.2.1 and will have an update of 4.2.2 by the end of the day.
If you are already on 22.214.171.124803, don't panic, no need to downgrade, your viewer is still safe. The bug makes doors and things 'look' broken, but it does not actually break anything, it's purely visual. However we ask that you update to 4.2.2 once it's available.
Thanks for your patience and understanding.
The Phoenix Firestorm Project, Inc.