@thisissami This has been covered previously on the FORUM, but generally, VM is handled by the network provider, not the phone manufacturer. The network provider handles HOW the device is notified that you have a VM. Sometimes, the set up is seamless because if you buy a phone from a network provider store, all those phones sold in that store are already are set up to work with that provider.
I have it set that I get text messages if someone leaves me a VM. Since Mudita Kompakt does not have a notification tray by default because the goal of the phone is to limit notifications, our team is currently working on adding the MWI, so users can have a visual indication that they have received a message. I know that the legacy carriers, like AT&T, Verizon, T-Mobile US use the WMI (Voice Mail Indicator which is then tied to their OWN Voice mail system), however, Certain VoIP or MVNO carriers (like Mint Mobile) use both, you just have to ask them to activate it.
The way it was explained to me (so please excuse the simplicity: When someone calls your Mudita Kompakt & leaves a message, that message is NOT stored on the phone, like on an OLD SCHOOL answering machine. That message is stored in the cell carriers VM system and the cell carrier then notifies you that you have a message. It’s not the manufacturer of the phone that makes that notification.
We understand that this could be a bit complicated if you’re used to certain functions working a specific way. That’s why our team is working on making the WMI feature available in a FUTURE update.
Hopefully this info helps clarify this aspect.