Apple got around to adding dual-SIM support to its iPhone lineup with the iPhone XS and iPhone XR lineup last year. Now building on that feature, Apple made a nice upgrade to iMessage in iOS 13 that will allow one to remain active on both numbers from the same device.
So, if you use the dual-SIM functionality of your iPhone XS, XS Max, or iPhone XR, you will be able to remain active in iMessage on both numbers post the iOS 13 update. Right now, once a user enables dual-SIM functionality on their 2018 iPhone, they have to select the number on which they would like to remain active on iMessage.
As the screenshot above shows, iMessage shows both numbers on which the user can remain active. Users can also select the default number from which they would initiate a new conversation, though they do get an option to switch to their other number from the message composer window. Messages sent to any of the two numbers would show up inside the Messages app.
This feature is going to be extremely useful for anyone who uses separate work and personal numbers as they will be able to remain active in iMessage on both numbers from the same device. Since the feature relies on dual-SIM capability, it is only going to be available on the iPhone XS, iPhone XS Max, and the iPhone XR.