Today is the last day that owners of pre-paid SIM cards in Poland have to comply with mandatory registration with their providers before their service is cut off.
The registration is the result of a law passed last year requiring all mobile numbers to be linked with the identity of the owner, ostensibly to curb terrorism. If you have bought your SIM card in the past six months or so, odds are you were already required to give the provider identifying information at the time of purchase.
If not, though, the good news is that complying is relatively easy and straightforward, and can usually be done online or in many physical locations in a matter of minutes. You will need your phone (obviously) as well as a PESEL, passport number, or residency card.
Check with your provider to see where and how to register: