IN response to the reply, i have the two sim XS, one Esim is ATT US phone, the other sim is Canadian Rogers phone line.
u cannot chose both SIM cards to use I messages on. ONE can use I message and one has to just use SMS.
when u use SMS it appears as a green colored Texted and with that u cannot see if it was delivered or even read. Its like texting to an android phone. and Vice versa when some sends u a note they dont know the above.
In the US the US phone line ATT does not charge u for texting inside the US. But since i do a lot of work and need the Canadian phone number, I message is a no charge feature that The Canadian line can use from the US to Canada thru the apple network.
SO it is not possible to have both numbers run imessage. IF u have a found a way please share it with us.
Secondly, when using my US phone line if someone calls on my Canadian line it automatically goes to VM. There is no way of knowing after u finish your conversation that there was a missed call or even a voice message on the Canadian line.
its a hit and miss that i call forward my Canadian line if i know i am going to be on the US line for a period of time so i dont miss a call or at least i know it was missed (forward to my work number) in order to work around this.
IF I am on my Canadian line talking and someone calls on my US line and i finish my call, again there is no notice or notification that someone called on the US line and i missed the call or have a voice message.
hope this all makes sense but so far nothing has changed and i have had this phone since december