Sensors on Enviro+

Can you please tell me if any sensors on the Enviro+ have been changed. I bought one that runs perfectly well when they first came out. I have just bought a new one and the temp sensor is reading 10 deg C low. It’s not CPU temp compensation, the low reading is too low for that. As I am trying to compare Air quality at sea level to Mountain values in Tenerife I need to be able to rely on the sensors.

It’s the BME280 on that model is it not? A couple of questions, if you’ll humour me.
Which OS are you using. Buster, Bullseye? 32bit or 64bit?
How long have you let the sensor ‘burn in’ for it first run.
The readings can take a while to settle down, I’ve found.

If you Enviro is mounted on a pHat stack or similar setup where its isolated away from the heat from the Pi’s SOC. Your going to want to remove the CPU temp compensation bit of code.

Thanks for your help and advice. I have 2 systems running, my original is on a zero, but I added a spacer contact strip to lift the Enviro another cm from the zero. There is still some effect, but I suspect I had a second contact problem that caused completely nonsense drops of about 10 deg in measurements. I had taken the compensation out of the program, but still got some heating. This is a problem as I am using the system as a portable sensor in a small enclosure while I’m hiking in the mountains. My answer has been to add a pi fan to the system, blowing over the Enviro board, this gets the board to air temp so all is fine. The system went up the mountain in my minibus last week , but at that time was not battery operated, now the system runs off an 8000mA power pack which gives about 10 hrs life. The system has accompanied us on 2 visits down Los Cristianos and this week will make two journeys in my Rucksack while we walk. Again thanks for your help