Not right away. You’ll be able to log in with both NemID and MitID throughout the migration period. However, signing with MitID won’t be available before December 2021. That’s because the signature component in MitID won’t be launched until then. Penneo will support signing with MitID as soon as possible after the signature component is launched. In the meantime, you must keep your NemID and use it when signing documents via Penneo.