Linux Fedora 22 was released this morning and two servers have been upgraded without issue… the smoothest upgrades yet.
Total time to complete the upgrade has been about an hour. About 10 minutes of that was the actual download of the 1000+ packages, and the remainder of that was the reboot and actual installation of packages.

The process goes something like this:
“yum update” to get to the latest point of the old stuff
“df -h” to make sure there is enough room everywhere, especially in the /boot partition
“fedup –network 22” and off you go
about 10-15 minutes later the 900-1300 pacakges will have been downloaded, and the system is set to reboot into the upgrade process
packages get installed, then the cleanup then another reboot.
The servers come up all the way as they are supposed to. DONE!

Both are now running Linux kernel 4.0.4-301.fc22.i686+PAE
yum has been deprecated so now we use dnf instead.

As a side note, our normal method to ssh in has broken. Teraterm v4.74 now comes up with an error
unexpected ssh2 message(80) on current stage(6)

I tracked down an upgrade to v4.86 and it too shows the same error.
Time to google “programs similar to teraterm” and find something called putty
putty works! it is also configurable and will probably be the default terminal client until teraterm gets fixed.

Updated: 2015 May 27
add a third server upgrade that went flawlessly. This one took about 55 minutes, probably due to its 1750+ packages that needed upgrading.

Updated: 2015 May 28
add a fourth server upgrade that went flawlessly. This one took about 30 minutes, with over 2500 packages that needed upgrading.