Here is quick summary about things should be checked before an F5 upgrade.
This is the general F5 support article with clips and there is nice info for VIPRION and VCMP systems:
This a great community article
Also if there is the F5 GTM/DNS module then there are some extra steps:
For BIG-IQ upgrade or for BIG-IQ to upgrade f5 devices:
For F5 devices with the F5 APM module after upgrade check if the installed F5 Edge Client software needs to be upgraded as it may not work with the new F5 APM TMOS version.
An issue I have seen is to install the new version in a volume and transferring the configuration from the old volume to the new but without activating it and then to activate it after a week and there would an old configuration during that week many changes were done on the old volume config, so better before an upgrade so save UCS just in case from the old volume/partition:
Some workarounds:
F5 RMA process general articles:
F5 general articles for RMA with or withour UCS as without UCS the system and network settings may need to be configured manually and the configuration to be synchronized from the active device to the rma device.
For F5 DNS/GTM there are special steps:
F5 RMA of VIPRION chassis or a blade as for example when the new blade is installed but the active software version on other blades and vcmp quests is missing then the blade will get stuck in quorum for the chassis or vcmp quest as the primary blade will not be able to update it. If there is single blade in the chassis better hope that there is saved UCS expecially if there are vCMP quests as then for every vcmp quest the system and network need to be manually configured and the other config can be synchronized from the other chassis and vcmp quests that are in HA cluster.
When loading UCS on the RMA device that has containing encrypted passwords or passphrases, you can check(I have never used the second article but it is nice to have if issues are seen on a vCMP system when a chassis is replaced):
In some rare cases the SCF files can be used for a missing configuration but better use config sync.
