I have a C400 which the system advises that the firmware is out of date. I can see the desired version in the upgrades, but any attempt to download ultimately fails. When it times out, the message indicates to check connectivity, etc., but there is no connectivity issue and the issue was in V15 as well. I can download all else. The firmware version on the Fanvil site also appears to be an earlier version (which is what I currently have) than that being offered by the 3CX upgrade process. Just curious if others have the issue.