MMS and group messages over wifi
I have to turn on cell data in order to get group texts or mms when it’s not another iPhone, is this normal or is there a setting I can change?
iPhone 11
Yes, it is normal. While Apple’s iMessage service is an internet service, carrier provided SMS and MMS are not. Both SMS and MMS use the cellular telephone voice channel for transmitting the text portion, and MMS uses the carrier’s cellular data network for the image or attachment portion. MMS cannot use the internet nor WiFi.
If your carrier supports WiFi calling, they may also support WiFi texting, but you still must have cellular data enabled for the WiFi calling routing system to work properly with MMS. SMS and MMS are old technologies, that pre-date the very existence of the internet.