We have a team responsible for maintaining our images, and releasing new ones as necessary, so an update to our FreeBSD image offerings is likely forthcoming, though I do not have a firm estimate at this time, unfortunately.
With that said, an upgrade to 10.3 from the 10.2 image, in my personal account, completed without issue using the standard method:
freebsd-update upgrade -r 10.3-RELEASE
and following a reboot, you may need to run the update install once more, you can verify using:
This method shouldn’t cause any issues with an existing 10.2 install, though I do recommend making a backup of any customizations to your rc.conf, etc.
Joseph D. Marhee
Customer Success Engineer