1.5.3 seems to be the newest version of master control?
I’ve got G2E (not D) currently with 1.5.2 and it works as unlocked.

Hi CPHrider,

After that just reconnect with the Sagway app and set the new max speed.
If it worked please provide your current firmware versions.
I'm wondering if I can upgrade firmware above master = 1.3.5, batt = 1.7.5.1, bt = 1.5.15.

Thanks!