It's always advised to use our hostname SIP servers (sip.fongo.com/voip.freephoneline.ca) and to not setup devices to bind to the IP addresses that a server may resolve to at any given time. As we continue to grow and scale as a company, so does the architecture that drives everything behind the scenes. Just like any large scale server deployment, be it VOIP, email, DNS, etc. the SIP proxy may resolve to any given node at any given time, and a different node another time; this makes for a more disaster proof setup, among many other advantages.
Our own ATAs, softphones and apps will deal with this seamlessly and don't have any troubles, but any BYOD users who have setup a more delicate or locked "down device" configuration above what we recommend (for devices where recommended configurations are available) may experience trouble until those restrictions are loosened up a bit. I'll suggest some better documentation in the online FAQ to better explain this for BYOD users too and encourage community members to help contribute to our "Device Configuration Sharing" section so we can build an accurate and robust library of configuration for third-party devices.
We always do our best to communicate major, planned maintenance and our new service status page should also be beneficial in communicating service impacting problems or maintenance:
http://status.fongo.com/
However, one thing to keep in mind is that just like any company, we are continually growing and enhancing our network and small changes and enhancements are being made day in and day out and aren't necessarily communicated unless they are deemed to be of high importance or service affecting. If we were to start communicating every little tweak being made then users would eventually start to ignore said communication and it would be more difficult to make sure the important messages are in fact not ignored.
More updates on the recent changes will become available in the near future.