[phowat]

I remember it also had native SIP support and you could configure an account to connect automatically only when the phone connected to a certain wifi network. So I had my work extension on when I connected to the work wifi. It was really nice

[simfree]

Now even Google has dropped the (rarely functional) SIP support in the dialer despite almost all voice traversing SIP to smartphones today.

Everyone has their silo'ed version of SIP plus a few extra features resold & repackaged as something unique and new to the market.