Right now they all seem to be using 1.1 and would like to force them onto http2 if this is possible.
At the moment I don’t think it is possible. This would require a KEP to explain the rationale and API desired, and cover tradeoffs and track feature lifecycle.
We have an app that only speaks http2 and so I was able to work around this (we are using Istio) by setting Istio’s http prober rewrite annotation on our deployment. But it would be nice to not have to do this. I suppose we could add http 1.1 support for only health endpoint as another workaround if there is no support (and none planned for future as of yet, apparently).
I was kind of surprised to learn this, but maybe many/most apps drop back to 1.1 even if they support http/3 or http/2.