Prefect does not maintain a single consolidated list of features due for deprecation and their timelines. However, they do try to avoid breaking changes in new releases. When a feature is deprecated, it is typically retained for at least three minor version releases or six months, whichever is longer. Usually, deprecated features come with new and improved alternatives. You'll see warnings about the deprecation when using those features, so you won't be left wondering "Was it something I said?" if your code suddenly acts up.
For more details on Prefect’s versioning and deprecation policies, you can check this
versioning document.
Given that Prefect 3.x is released, it might be wise to start planning for an upgrade, especially if there are features in 3.x that would benefit your workflows. If you'd like more information on Prefect 3.x, exploring the release notes and new documentation can help make that decision easier.