I'm facing a similar issue, where the server in my cordova app (server based on https://github.com/zwopple/PocketSocket) actually crashes if a iOS 15 client (iOS 15.0.2 in this particular case) tries to send data. The error happens here: // inflate if necessary if(_pmdEnabled && !frame->control && (frame->rsv1 || _initialFrame->rsv1)) { (Line 682 of PSWebSocketDriver.m of said library) The error message marks this as the source of the error: _initialFrame And this is the error: Thread 30: EXC_BAD_ACCESS (code=1, address=0x9) I've tested sending messages to the public websocket server test page https://libwebsockets.org/testserver/, mentioned by @DirtyHerri. The connection is established, but if I send data using the "Send Junk" button, the connection is closed, so I guess something similar is happening there. Toggling NSURLSession WebSocket in Safaris experimental features section doesn't have any effect for me.

Did you find a solution? I've got the same issue.

Did you find a solution, @Ulix ? Got the same issue here.

@Momeks and @jq1106 - did you find a solution?

Same situation here. @Biochili - how do you plan to make the broken release unavailable and give iOS 12 users access to an older build? I don't see how to do that in AppStore Connect.

@Biochili @testing321 you're mentioning a fix. Does that mean that I can now again release builds which will work on iOS 12? Or could you clarify what you mean by that? Thanks!