What is the commonly followed procedure, because there are several, some include turning off imessage on your old device, some include telling your contacts who still use iphone to check the send as SMS button on their device, some include calling Apple and having them deregister your number, some include having the iphone user delete the contact, and then readd them, some include having the iphone user change the "description" of the number to Mobile instead of iPhone, and the list goes on, so which is it? There has been NO RELEASE from APPLE saying what the proper procedure is to follow, these are trial and error suggestions from users (obviously not stupid, if they can troubleshoot better than Apple, who appear to be the dumbfounded and stupid ones). It is not a glitch, you are right... it's a Problem, and not USER error. You yourself even admit that the group messaging is still a problem, and not fixable at the moment, but that must be all of us users...
And when I got my iphone going from android, imessage was instant, it didn't take any time... It is an apple problem... but the Fanboys will never let the big corporate machine take the hit... no...
I don't have to figure it out and offer the solution, I am not the corporation that created the problem, I am not under obligation to the end user, the creator is.
As for the FIX, my family members have all updated their devices... I can receive text messages from them, except from group...
However, when we got iPhones, we didn't have to do anything, iMessage took over automatically, and the same should be in reverse... a USER, and especially THEIR CONTACTS should not have to jump through hoops to have something change back to the way it was originally.