I don't have an answer for you, but I have a caution...
I once worked for AT&T and worked on AT&T Messages.
DO NOT USE IT, if it still exists, if you're with AT&T. At the time I worked on it, there was no encryption except in-flight (https) -- which means if I had had production access (and some people who worked there at my level, definitely did), I could have read all messages, blobs, everything. I was told after I quit that they intended to add encryption, but since AT&T would still hold the keys, it's useless.