NimbostratusHello Experts
I am planning to upgrade F5 LTM 3600 OS from 11.2 to 11.6 or latest. But I heard there is significant configuration changes related to irules and class of ASM.
Can any body tell me that after 11.2 to 11.6 upgrade, there will be no issue with current configurations?
CirrostratusNo, nobody can. You'll need to take a very close look at the release notes for each version since 11.2 through to 11.6 and pay particular attention to any behaviour changes listed.
I'd also highly recommend you do a search here at DC for 'upgrade' and trawl through the results to find out about any 'gotchas' and the like.
Ideally, you would test the upgrade in advance on a test box. If that isn't possible, I'd plan and prepare for issues (and possibly rollback) the first time you try this.
MVPwe can't give you a recommended version. it depends on your needs and internal policies. personally i play it safe and use 11.5.1 currently if there isn't a huge need for any of the features of 11.6.
and yes you can upgrade from 11.2.1 to 11.5.1 or 11.6.0 directly.
as for your upgrade, if you have a partner you could ask them for advise and assistance. they probably done an upgrade before and know a little bit better what can turn up. but even then it remains not fully predictable.