I think that'll be a problem. Since you'd be recording your historical data off of the MQTT server, and your phone wont be updating the MQTT server, you'd have

I think that'll be a problem. Since you'd be recording your historical data off of the MQTT server, and your phone wont be updating the MQTT server, you'd have gaps in your data. Sounds like you want to record data right on your phone. Some other commenters have mentioned possible alternatives that probably would work better for you.