Asking for a colleague that bought Dorico 2 some days ago. He makes use of the “grace period” to get Dorico 3. He has downloaded Dorico 3. The problem is, that he hasn’t got a new activation code, so he is stuck.
I answer in FB too :
https://www.steinberg.net/forums/viewtopic.php?f=246&t=167376&p=894707&hilit=grace+period#p894707
If you are eligible for a Grace Period upgrade, run the Maintenance procedure in eLicenser Control Center. That should pick up your upgraded Dorico licence.