Is the procedure to reactivate SambaPOS license(from one db to another) same with the new reseller setup?

Except changing to cp.sambapos.com instead of the old sambamarket.com, basically everything should be same, correct?

Just want to be sure before I upgrade my db to SQL Express 2017. Anyone has recently done a migration?

If you are just upgrading the database it shoouldn’t affect the license. If you are uninstalling and reinstalling or physically moving the database it might affect it.