Charlie,
I updated 2 SME servers locally and 2 servers remotely. I have 2 remote locations connected by IPSEC VPNs. I used putty for all connections from my laptop. I timed the reboots so that all would be down at approximately the same time with the central server rebooting about 30 seconds prior to the others. When they came backup, I tested the vpns with a ping. They both failed. Further inspection revealled the keys set in the IPSEC VPN settings showed different encryption keys than the actual keys show by the 'click to view' on the remote server. The 'click to view' on each upgraded server has changed. The IPSEC VPN settings showed the old key for the remote server. No other services have been affected that I am aware of.
I reconfigured IPSEC VPN on each server using the current (keys) and everything is working fine again.
I hope this clarifies my situation for you.
Ryan