We have 2 Big-IP 3600's that we want to re-purpose for dev/qa use. I know the support has expired and they are running old firmware, 9.4.8.
Can the latest or next to latest, 12x or 13x be loaded on them?
Since this is just for dev and qa use, are there reduced cost options for licensing? This is guessing we will need some sort of contract to access downloads?
Since this is a re-use and we do not care about saving any configurations, can we go directly to 12x or 13x?
3600 Appliance supports up to BigIP 12.1.2 software. Check HW/SW compatibility matrix for details https://support.f5.com/csp/article/K9476. There are license check date requirements though. Check here for License-Check-Date/SF compatibility matrix https://support.f5.com/csp/article/K7727
You can renew support to raise your License-Check-Date but this can be costly. And even then, you'll only ever get to install BigIP 12.1.2 software and no later. Not sure if it's enough or not for your lab, you'll be the judge. Jumping from v9 to 12 is not a major hassle if you're happy with factory default configuration. If you run into issues, use BigIP 10.2.4 as your stepping stone. If 10.2.4 to v12.1.2 upgrade doesn't end well, use BigIP 11.4 as another stepping stone.
Also check this article by Chase Abbott regarding developer VE license (10Mbps) which suits perfectly for dev/test environments. Unlike with BigIP 3600 that limits you to 12.1.2 or older, you can use VE dev license with all current versions. https://devcentral.f5.com/articles/f5-developer-edition-how-to-obtain-a-developer-license-key