Continuing the discussion from Tasmota - additional sensors created on FW update:
TL;DR - a HowTo for updating Tasmota devices in use with HA 
I’d notice a number of errors like this in devices flashed with Tasmota
Entity sensor.sw7_energy_current (<class 'homeassistant.components.mqtt.sensor.MqttSensor'>) is using native unit of measurement 'A' which is not a valid unit for the device class ('power') it is using; expected one of ['kW', 'W'];
The reason is I was using an old version of Tasmota that doesn’t support the new device classes etc. Personally, I had some very old Firmware (back to 8.1).
Firstly, a Warning: do not rush the devices, if you do, you might brick them. I used TDM to monitor the console output and the web interface, so I could see what was happening. I rushed one of the first devices I did and bricked it.
Secondly - the web interface doesn’t always update when it is finished. It might still say Minimal Firmware - please update but actually, the web page has not refreshed - just click on a different page and then back to the main menu and the warning goes - but remember the first item (don’t rush it).
Thirdly, for me, I restored all the MQTT topics back to the default on the Tasmota device. However, if you have any templates or other systems processing the data, you will need to amend those to match.
Finally, be careful which Tasmota binary you use. By default the upgrade page points you to the -lite version. I could not work out why my DS18B20 sensors didn’t work until I realised they needed the full binary.
Note that the device will not appear in the Tasmota Integration until you get past version 9.1 to the latest version (you need to update in order as per Upgrading - Tasmota). However, the devices and entities will appear automatically as the old SetOption19 is now on by default (even if it was off before). I did it in stages, updating everything to each stage (Current → 8.5.1 → 9.1 → latest).
Once updated, you will then have every sensor twice (once from the old MQTT Integration and once from the Tasmota Integration).
To restore the status quo, go to the Tasmota integration and open the device.
Click on the 3 dots next to the Device Info, and select 'Remove device from MQTT`
Then go to the entities page and filter on the device name and delete the _2 from the remaining entities.
If you have renamed some entities, you will need to go and do a bit of editing to get things back, possibly update helpers, groups, schedules and automations as well in some cases to get everything back to where it was
Final thought, the button entity has gone
HTH.