These unlocked specialization's?

Do you only unlock them for that week or do you keep them forever?

Forever! Which is great for everyone. I think it’s a good stratergy to unlock 2 every week.

You unlock them forever

Thats not a bad idea…open specialisations for a limited time and you have to complete it in that time frame or lose the chance to ever have it

It would be mean, but fun…then you can repeat it over the year!