I just did that.
What I did was install an app (can't remember the name now and I've already deleted it). You give it permission to access your messages, on your old phone. It makes a copy of all the messages to a file. You copy the file to your new phone (I used thumb drive)
Then you install the app on the new phone. And process the new messages file, which your messages app on the graphene app has access to.
Looking it up now, I think the app was SMS Backup and Restore.