The tax office, which is responsible for population registration in Sweden, will send a letter to all who live in apartment buildings. They ask for the national apartment number, because you now must be registered at your apartment instead of, as previously on the building you live in.
We have previously sent a letter to all tenants with the national apartment number. We will also mark up all the name lists in the stairwell with this number. Due to technical problems, we have not yet started with the markup.
If you have lost your letter with the national apartment number, you will find it on "My pages" - "My contracts".