I found two Issues with Upgrade to 4.4, actually this might be board specific since I have seen this issue before.
Copy 4.4 Complete package file over to router via winbox, reboot. Does its thing, comes back online, router APPEARS to be working, well It is Everything on LAN side is accessible, and the three ports I have on a WAN side for VOIP and cable connection, ( eg ehters 2, 3 and 4 are on a bridge of their own) the VoIP phones work.
The problem is that there is NO NAT translation, and no internet accessibility from the LAN side, a Reboot does not fix the issue. Restoring the backup I just created before the upgrade will fix the issue after it restores and reboots.
This is where I found the second "bug" If you DOUBLE click on your backup file, a new window pops up, shwoing file name, TYPE Backup, Size 398.9KiB, Creation Date: Dec 24 2009.... If you click on restore in this new window you get: Do you want to restore config and reboot, you click YES, then you get Winbox error " Couldn't Restore configuration - no filename (5) "
BUT if you click your backup file ONE time in the file list, and restore at the top of the file list window, it will restore and reboot and work.
Not a big issue but caught my attention.
The real question I have is Why does my 493AH always have NAT issues after an upgrade, and on occasion at random times about every month or 1.5 months it will just stop NATTING, without being reboot, or without an upgrade. I have noticed though that on all the recent upgrades, 4.X it happens every time.