RCS sent group text messages not received by iPhones on IOS 16.7.11

I have an iPhone 8 Plus on IOS 16.7.11 and after 8/12/2025 I was not able to receive group text messages with group members that have android phones. I went over this with T-mobile, apple support, and apple genius bar (caseid: 1026809*****). I tried to tell the support folks at apple that my IOS is not capable to receive Rich Communication Services (RCS) texts so how could a change be put in the network that would send a text message with a protocol that a bunch of iPhone users are not able to receive? I received no solution from apple and they simply said upgrade to a phone that can support IOS 18 which can handle (RCS). So I told the android users in the group to indicate me as SMS/MMS only. That worked for the android users sending text messages to me within the group. However, IOS 18 does not provide a mechanism to indicate that a person in the group is not able to receive RCS text messages so I still won't be able to see the text message within the group from apple IOS 18 phones.

[Edited by Moderator]