Recommended Version

I haven't seen any articles where F5 has a gold standard code version and in every instance where I have had issues with an F5 device they recommend upgrading the latest software out for the particular hardware in question. I believe the current right now is 17.5.1. I would make sure that you are able to upgrade directly from your current code version, which can be verified at the following link.

https://my.f5.com/manage/s/article/K13845

In addition, make sure that your license check date matches the minimum requirement list in the following link.

https://my.f5.com/manage/s/article/K7727

The license check date should be done prior to installing the new software or booting to the new software otherwise the configuration will not load. Additionally, make sure that you have a backup of your device as well as a backup of the master key otherwise the import of the backup will not load properly either.

https://my.f5.com/manage/s/article/K5903

version other than x.0 are long term support versions.

for upgrade, i'd choose 17.1.latest as it is 2 years old version while 17.5 is 6 month old.