(In reply to Ritu Kothari (:ritu) from comment #4)
Hi Dragana, is there a way to narrow down the users that might be impacted by bug 1523427 rather than turning it off for all of release population? This is to mitigate the risk mentioned in comment 3.
There is no way to narrow down the users that might be impacted by bug 1523427.
The pref turns off the websocket over http/2 feature. Firefox will still support websockets over http1. With the pref turn on, if a server do not support the websocket over http/2 feature, Firefox will use websockets over http1. Therefore both code paths were tested in nightly and beta.
The websocket over http/2 feature is a new feature and there is not a lot of servers that support it (this might be the reason we discovered it so late). Therefore, I believe that nightly 65 and beta 65 users have mostly used the websockets over http1 code path. Risk of turning off the pref is very very low.