It seems that in v15 the failover process does absolutely no logging to the Windows Event Log (which can then be picked up by 3rd party tools such as RMM). My failover scripts do extensive logging so I can see exactly what they did and when - but without 3CX logging, I can't see why the failover triggered. What's worse is that so far in the last two days support haven't been able to tell me one single place it does log to, so as far as I can see failover runs completely without logging of any sort. This is a feature that needs to be well documented, stable, bulletproof but above all predictable and tell you what it's doing and why. So far it's not doing well on any of those criteria.