From what I can tell, kube-runtime v0.63 does not work with k8s-openapi versions before v1.19 due to this line:

https://github.com/kube-rs/kube-rs/blob/16c4bf2389529ace6a2b784bfd71b91103be2198/kube-runtime/src/events.rs#L3

because the events API was not at v1 before v1.19. We get the following error:

error[E0432]: unresolved import `k8s_openapi::api::events::v1`
 --> /home/ver/.cargo/registry/src/github.com-1ecc6299db9ec823/kube-runtime-0.63.1/src/events.rs:3:46
  |
3 |     api::{core::v1::ObjectReference, events::v1::Event as CoreEvent},
  |                                              ^^ could not find `v1` in `events`

Practically, 1.19 is probably a perfectly reasonable minimum supported version at this point. But this was a surprise to us since Linkerd's minimum supported version is currently 1.17, so we either need to bump our minimum version or stay on v0.61.

Ignoring Linkerd's issues... I think kube needs to be explicit about its minimum supported version and communicate (i.e. in release notes, and ultimately semver) when support for a version is dropped. I'd even propose that kube re-export k8s-openapi with features for each of its supported versions so that this compatibility matrix is made explicit in kube's features.