[archi42]

Uh, I think my friend ordered one locally and (because that was the last one in stock) another one for his parents from AliExpress.

I didn't do the replacement, but it seems reasonably simple - the cylindrical sensor unit has a cable with a 4 pin connector and is clipped in place.

The new one doesn't look exactly like the old one and had different makings. I hope this means it now doesn't randomly fail.