I found the following description about supported docker versions
in kubernetes v1.18 and 1.19 documents.
The Kubernetes release notes list which versions of Docker are compatible with that version of Kubernetes.
But I cannot find supported docker versions
in the Relase Notes.
v1.18 Release Notes
v1.19 Release Notes
Also, I check the other k8s documents.
v1.15 and v1.16 document describe supported docker versions
.
The documents specifically list them.
v1.15 Release Notes
v1.16 Release Notes
The list of validated docker versions remains unchanged.
The current list is 1.13.1, 17.03, 17.06, 17.09, 18.06, 18.09. (#72823, #72831)
As per https://kops.sigs.k8s.io/releases/1.19-notes/ the Docker 19.03.11 for Kubernetes 1.18+ will be supported.