I can't send/receive MMS from non-iPhone users after iOS 8.4.1 update

I have an iPhone 5 and am a Straight Talk BYOP subscriber and am unable to send and receive MMS from non-iPhone users since the iOS 8.4.1 update. I can receive text only messages, but no photos. I had this problem before and fixed it by adjusting my APN settings, but the ones I've used so far don't work. Is anyone else having this problem? Any suggestions?