Re: Sailfish X mms not working on MetroPCS
 

If you're able to use epc, do so. I've had countless issues on fast., and the older APNs. ipv6 on MMS, dual on Data. Prefer 4G. Done.

Re: Sailfish X mms not working on MetroPCS
 

My latest provider wanted me to send a mms first before receiving mmses was enabled/unlocked.

Re: Sailfish X mms not working on MetroPCS
 

I've been using fast for months now. Not a single problem. Glad epc fixed your issues.

Re: Sailfish X mms not working on MetroPCS
 

I can confirm that fast.tmobile.com works great on my Nexus 5 with SFOS, but inconsistently on my Xperia X with SFOS.

My observations:

Nexus 5 - I get advertised LTE data speeds on fast. For MMS, I just switch to epc to get it to work.

Xperia X - I don't get data speeds approaching what I got using SFOS on the Nexus 5. In fact, on the Xperia X, performance on fast actually seems worse than on epc. In any event, I'm using epc: I'm not getting LTE speeds, but at least performance is reasonable and consistent.

Re: Sailfish X mms not working on MetroPCS
 

Another datapoint with Xperia X running Sailfish on T-mobile:
fast.t-mobile.com
IPv6
No proxy
http://mms.msg.eng.t-mobile.com/mms/wapenc

This works but only if not connected to WiFi at the same time.