MtoA 18.104.22.168 wasn't officially released because it was something we backported to go into Maya 2017 update 4. MtoA 2.0 had already been released, but we didn't want the Maya 2017 Update 4 install to force everyone to update to Arnold 5, because that would have caused a lot of problems. We wanted users to be able to choose: stay with Arnold 4 for now, or update to Arnold 5 when ready.
Arnold 22.214.171.124 now reports the file handle limit used at the top of the log and if the limit is hit, we print out a list of all the open files in order to aid in determining why there are so many files open at the same time
From Arnold 126.96.36.199 we fixed the timeout produced by RLM broadcasting for a license server in the LAN (and failing). Now, every node using arnold should point to a valid RLM server by the regular means: env vars, lic files, etc. (or it will fail instantly without any delay).