Forum Discussion
mikeshimkus_111
Oct 15, 2015Historic F5 Account
Hi Panda 01, mixing versions of BIG-IP in an HA pair can cause unexpected results. I recommend either upgrading both boxes together, or creating new partitions on both that you can upgrade. If it fails after you've upgraded the new partitions on both boxes, you can reboot to your 11.5 partitions.
Here's some guidance on upgrading HA pairs: https://support.f5.com/kb/en-us/solutions/public/11000/300/sol11318.html
(That's for v10, the v11 link is broken).