Pursuant to the Law on Higher Education and Science dated July 20, 2018 (art. 51b sec. 4 and art. 198b) – student IDs remain valid over the period of limited or suspended functioning of the university and 60 days after return to regular functioning, without the need of confirming the validity.
Hence, all IDs that were validated with a stamp dated 31.03.2020 or 31.10.2020 remain valid until November 29, 2021, without the need of validating it at the office (and obtaining a new sticker). Information on the legal basis of the above (in Polish only): here.