I have a Fanvil i10SV doorbell front and i20 for the back.
Both doorbell boxes support video.
I have x5u, x6u-v1, x6u-v2, and h2u phones setup in a Doorbell Ring Group.
Not sure when, but I think after I added th x6u-v2 phone, the only phone that rings is the x6u-v1 when the i10SV button is...