Live device is: SONOFFRE (SonoffRe) and is fitted as a central heating controller in a live system. It is a Sonoff Standard Switch, upgraded with the larger 32Mbit EEPROM to give equivalent storage to a Wemos d1mini
Devices being tested are: SONOFFDEV (local hardware copy of the live system) and HEATINGINVESTIGATION (A Wemos d1mini)
SonoffRe calls home on every boot (still with v1.0.5 firmware) and downloads the latest (currently v1.0.7) but does not apply that firmware, repeating the process next time.
Replacing the app firmware causes the two test devices to upgrade, but the live one remains on v1.0.5.
The only difference in handling of these devices is that I managed to send the VirginSoil app to the SONOFFDEV device with the startup directive to carry out a full erase of EEPROM, which then required re-introducing to WiFi.