Session are getting dropped post upgrade 15.x.x

[BB16]

Session are getting dropped post upgrade 15.x.x and sessions are not seen in traffic log to analyze further.

Previously was working fine. Every config is iRule based like iRule is attached to VS.

what could be possible workaround or solution, please help.

F5 LTM is used as webproxy. Also help how to log dropped traffic on F5.

[JRahm]

I suggest you open a case with support since you are experiencing degraded performance. Some thoughts to consider as you work through the issue:

1. Did you read all the release notes and note the changes of behavior and known issues?
2. Did you test in a lab against production-like traffic?
3. Do you maintain default profile settings or customize them all to avoid default behavior changes?
4. Is your failure-over device still on the old version and can you fail back to check discrepancy?