If your membership is still active, or you are a lifetime member, the most recent updates are still available for you to download and install from My Account / My Products.
But since the store has closed, there is no way to renew a membership there if it has lapsed. The last product you owned should still be there though.
I assume that any Cakewalk redemption codes that may be available through 3rd party retailers would still be honored. But I have noticed that some retailers have already updated their online stores with "product no longer available" notes. But seriously, I wouldn't sink any more money into this product! Just keep what you have and use it until the wheels fall off!