Multimedia message proxy: 188.8.131.52
Multimedia message port: 80
For running Verizon custom ROMs on Sprint phones, this APN setting will allow everything to work including 3G, 4G LTE, SMS sending/receiving, and MMS receiving. But MMS sending will not work!
There is a work-around this, just use 8SMS app, which can replace your SMS app and also allow you to send MMS. (install and enable, that’s it!)
If 3rd party apps don’t work, you will have to re-install stock Sprint MMS APK on your custom ROM (if using custom ROM).