Hey Scott.. Thanks... Yeah a few days I had already seen your Forum post with Eskimo about iCloud Frame Relay and I checked with customers and subsequently ruled it out as a cause of the problem. This morning we actually discovered the real cause of our problem... On one of our users experiencing the problem at the BSD socket level getaddrinfo was resolving to BOTH an IPv4 and IPv6 address. My code only ever tried to connect on iPv6 in that case. That failed to connect presumably because the cellular provider has some type of fault. They are newer 5G networks here in Europe. I tried a new testflight version with customer this morning that will now try to connect to IPv4 instead if that happens and it fixed the problem!!!! It was another forum item I saw from Eskimo https://developer.apple.com/forums/thread/48996?answerId=146136022#146136022 which pointed me in this direction where he says "BSD Sockets requires you to call getaddrinfo and then write a loop over each returned address, opening and connecting the socket, until you get one that works. Doing that reasonably well requires some ugly code, code that can’t be as good as the OS’s implementation!! That man Eskimo is a genius and saved me a ton of work!! I was close to starting a major rewrite of our App to use higher level networking code. Thanks for your help

No.. I just moved on and accepted it! Have not rechecked recently. Too busy with other stuff.

Hi.... We are using BSD Socket code too (For last 9 years) and have recently had some reports (So far only on iPhone 13 and iOS15.x) of sockets not connecting. However it is only a problem when connected on WAN. If user switches to WIFI then everything is OK. From your experience with the problem does changing from WAN to Wifi make any difference? i'm not sure if what we car seeing could be this issue or something else.

In addition to the issue with the Colon .. I also notice that Upper Case Letters are displayed as Lower Case So if I offer "Dave Maj" as the text then on the incoming Call Screen it shows as "dave maj" but later in the iPhone native phone App Recent list it is displayed correctly as "Dave Maj". This is all still happening in iOS15 Beta 6

Further to this after further experimentation... Anything to the right of the Colon is shown but anything to the left of and including the Colon is not shown on the calling screen!!?