Currently T-Mobile blocks Androids built in Visual Voicemail from showing inside the stock Android Phone dialer. Due to the built in block, it forces you to use T-Mobiles app which is riddled with bugs and doesn't notify you about a new message. I have T-Mobile Jump On Demand and I am able to switch phones a lot due to this. I have had in excess of 30 different Android devices with various Android versions and T-Mobile Visual Voicemail app version and still experience the same issues. Their app is flawed and should be a option not a requirement if you want Visual Voicemail. This notification failure and app failure has caused me to miss important voicemails. The only Android devices they are unable to block is the Google Pixel and OnePlus due to both having workarounds to enable stock Visual Voicemail.