It really depends on your deployment, but a lot of us have adopted HTTP/2 without lifting a finger, or with routine dependency updates. It’s possible (probable) that those migrations have not resulted in optimal usage, but neither have specially tailored migrations (see: the sad slow death of Server Push).

As far as whether you should consider migrating, it’s worth doing a quick spike to determine level of effort. I expect the number of use cars which:

- can’t trivially update

- aren’t directly providing HTTP functionality to users who expect that

… is a rather small niche.