This worked perfectly! - except that all imported messages now have changed timestamp to the import time. But all messages are there - thank you so much!

I've exported all old sms'es (messages) from my old Android phone to a 3.57 MB .json file and sent it to my new Volla Plinius running Volla OS 15. But when I go into the default messaging app, choose settings and "Import messages", when I select the .json file it immediately just says &quo...