Originally posted by MonthOLDpickle:

Does that require a downgrade? If so..how?

Maybe. But, in fact, 12.15 and 12.16 has a web-site compatibility issues.

Is there anything to worry about a stock 12.14..running really slow?

No. 12.14 is a way better.
Don't forget to disable update warnings (opera:config#UserPrefs|DisableOperaPackageAutoUpdate = enable).

ETA: http://www.twitch.tv/directory broken in 12.16(x64, Windows).