Group RCS/SMS threads failing on iOS 18

[mtosch]

Just upgraded to iOS 18 final release. Group Messages threads where there is mixed RCS and SMS support seem to be broken. Running iOS 18, I can’t send or receive messages in the thread. Others, including older iOS, are not impacted.

Resolved by disabling RCS support and rebooting. Now it’s back to a regular group sms and it works just fine.

 

[mnsportsgeek]

I haven't had this issue with existing mms group chats.

 

[FilmYak]

My group thread on RCS — 6 iPhone users, all of us on ios18 — and 1 android user — is an utter mess. Has broken into multiple group threads, lost the name of the chat, all sorts of issues.

 

[Larrupin]

My group chat (3 iPhones 1 Android) was working great using RCS but tonight it’s randomly switching to iMessage, sending some people the message in another text, etc….. Restarting, hard reset, turning off iMessage, etc….does not solve the problem. Hopefully it’s a glitch that will go away soon.

 

[TimFL1]

Apples RCS groups implementation is a mess.

All your issues stem from Apple treating RCS and SMS/MMS as one tier of communication (Text Messages), switching between them on the fly. This goes actively against what the Universal Profile specifies and what other messengers implemented (e.g. Google Messages). You are not supposed to be able to send SMS/MMS into a RCS group chat, Apple should prevent this and never have a group chat downgrade to SMS for you (that is what other apps do, it‘s the reason why you create duplicate MMS groups for them whenever you send non-RCS into the group chats). If you, for whatever reason, need to downgrade to a MMS group (e.g. cause one participant disabled RCS), you should be prompted to create a new group instead just like they do with iMessage.

Both texting standards aren‘t even compatible, MMS groups usually cap out at 10 users whereas RCS specifies 100 as the sweet spot, so not sure why Apple is so adamant about merging the two standards for group messaging.

Here is a detailed discussion outlining the group chat issues Apple‘s implementation causes: https://forums.macrumors.com/threads/rcs-supported-carriers.2429980/post-33282636