While the provider should continue to work for older versions, we don’t officially support them. This matches upstream’s support policy:
https://kubernetes.io/docs/setup/release/version-skew-policy/#supported-versions
Basically, this means that fixes will not be a priority for any bugs that only apply to unsupported k8s versions. Practically speaking, I haven’t seen any bugs like that since k8s 1.6, so it may not be an issue.
Keep in mind that our SDK is generated from k8s’ OpenAPI schema, and it’s possible/likely that they will remove unsupported apiVersions once they roll out of the support window. For the apiVersions removed in 1.16, that would likely be the 1.18 release (~March 2020). At that point, you’d need to be on a version in the support window, or stop tracking current pulumi/kubernetes releases.