I use Message+ on three devices. S10, Tab3, and a PC with W10. All 3 have the current operating systems and Messaging app. They are all linked to my cell phone number. None of the devices syncronize. This has been a thread here for a number of years and I have not seen a cogent solution from Verizon. If I generate a message on one device it is very important that it and any response shows up on the other devices. This does not happen, the response shows up on the device which generated the original message. and not the others. Since messaging is an important part of the service Verizon provides I would think that they would put more emphasis on getting their software to function properly.