Well, for grins this afternoon, I sent a message from my Win 10 laptop running Message+ v1.0.17.0 to a VZW contact with a Pixel phone. The outgoing message sync'ed on my Win 10 desktop running the web access and on my iPad running Message+ app v3 something. It DID NOT  show up on my Droid Turbo 2 phone, primary Integrated Messaging device.  I did receive a response on my Droid from my contact, so the message was delivered, but the response DID NOT sync on my Win 10 devices. On my Droid Message+ app, I went into Settings->Account and did a Restore Messages, From Online....Go figure, the original outgoing message now shows up on my Droid....go figure....