Since some time now docker is being on the fall and is being abandoned as provider for container technology.
Red Hat already threw docker out of its Red Hat Enterprise Linux (all Versions 6,7 and 8) last year. The Cloud Native Computing Foundation replaced docker as recommended container technology with CRI-O (Container Runtime Interface) as best practice.
Furthermore the acquisition of Docker Enterprises(=Docker Swarm Product) part of Docker Inc. by Mirantis is a clear sign of its current declining meaning for its future in the area of containers.
Red Hats way is to foster CRI-O (the runtime system) and podman (the management cli tools). CRI-O is better in ways of using less system resources. Also CRI-O does not use an additional daemon as docker does.
For migration simplicity podman is designed to have the commands very similar/identical to the corresponding docker commands. As I understood, the CRI-O maintains compatibility to dockerfiles and images, so a migration will be easy.
Nice to look at: The Cloud Native Computing Foundation Interactive Landscape