[2021] Windows store Lem Update 3.1

If you run the Downloads and Updates function in the MS store app it will find and apply 3.1.1  

Vishniac said: What about Steam?

My game remains at 3.0.2 even though Auto-update is activated and I have all DLCs/expansions required.
Some solution?

Then most likely you have opted into 3.02 in the Steam betas tab, which tells Steam you don't want to update. Opt out of all betas there.