Yes, I moved several phones over without a proper planned works notice. I know we had lots of notices about new call server, but nothing saying explicitly when we would be trying to move lines over. It should have "just worked". For many it did. Sorry. I have been told off by my staff :-(
Sadly several people had issues and I made changes to work around some of them during the day.
What has been bugging me is the call server has crashed half a dozen times. Thankfully, unlike asterisk, calls in progress are not affected by it crashing, and it restarts in a few milliseconds - we just lose billing data. So not a major headache.
So I have been adding debug messages each time, and working through tcpdumps, and finally found the correlation. Every time one of my sky boxes at home tries to call home (via a sipura), bang! it crashes. So I have the offending message and should have it sorted in a few minutes.