What's being upgraded exactly? And why
26 devs have now voiced their opinion for covenant upgrades to bitcoin.
So far CTV is the only op code to not have any one left evaluating it which makes sense since it's the most mature. CTV also has the least amount of "No"s without any "Evaluating"s.
If you're a bitcoin developer and haven't voiced your opinion yet we'd really appreciate it so the community can be as informed as possible.
https://en.bitcoin.it/wiki/Covenants_support
Soon we'll be moving on to additional stake holders.
Discussion
Each one has a link to the BIP. Reading that is probably the best place to start to learn about them.
Each one of these proposals have a BIP that you can read. You can see all the features each one offers at https://utxos.org/alternatives