I have loaded and am current running -rc4.  It seems to work well.  There are a couple of caveats and the potential for some chaos in the January VHF contest:

1. For the entire v2.x series MSK144 generated by version 1.9.1 cannot be decoded by V2.x and visa-versa.  The GA release of v2.x should be out before December 31 and I suggest we all need to be on it.
2. Effective with -rc4 the system only supports the 77 bit version of the FT8 messages.  That means -rc4 cannot decode messages generated by 1.9.1 and the other way around.  For now -rc4 users are staying above 2000 Hz to try and minimize confusion. With the GA release of v2.x due the end of December there could be some adventures as people who have not been keeping track of developments  start reporting "no decodes.".  Again, for the contest suggest we all need to be on V2.x
3. In the good news column, v2.x autosequence handles NA contest mode exchanges and "casual" (signal report) exchanges very nicely.  So that should take care of that problem.  No more switching back and forth midstream as contesters and general users get all mixed together.

Hope to see you all on the air for the January contest.  If you do decide to use FT8 or MSK144 probably time to upgrade to -rc4 for a trial run and to the GA release NLT December 31 for sure.  here is the URL:

Johnny K4SQC