We use "now Extreme" Wi-Fi since AP300, 5131 and WS2000.
Is fact: some versions have problems with new feature or reliable conn.
The recomendation for specialists is: keep up to date software.
My version: Read release notes and check: working is reliable? no problems? from this to this have critical bug? is mandatory for me or my client keep updated? i need feature from new version?
Version 18.104.22.168 and 22.214.171.124 is the worst version for me, but here is initial version from 7.1. We stay in 126.96.36.199 and problem at now, no have problems.
Extreme, please release three versions, the "legacy" focused in reliable software, with no new features but critical bugs fixed (no vulnerabilities), one "stable" with new features but issues may occur and one called under development, to test and validate with specific customers.