We have installed many extensions 2.0 on Dynatrace console and on the AG server and we want to know how we will be able to maintain the life cycle of these extension automatically without any manual action. Does extensions are updated in their new version during the update of the AG or does it need other action for that? (like download the new zip on Dynatrace console and on the server also manually).
If, as your post mentions, this is just about extensions 2.0 in Dynatrace, you just need to update the extension and its related activations in the Dynatrace UI, the new version is downloaded from the cluster automatically by the ActiveGate or OneAgent and you don't need to worry about that part of the process.
These two buttons on the UI are enough, which you can also trigger via the API for further automation.