Collection Upgrades are like NFT upgrades, except that now an entire collection is being targeted for the upgrade instead of just one NFT. Editions can also be upgraded in the same way. When doing a collection upgrade, traits within that collection can also be targeted.
To do a collection upgrade, the NFT collection has to have been minted. Only the creator wallet address can upgrade the collection with unlockable content only accessible by owners of an NFT from the collection or also target specific traits of NFTs in the collection.
Read more about Collection upgrades and how to enable them in your own app in the