There are ingress controllers for kubernetes that support setting up routing rules that would fit your needs. For example, the user's browser could set a header

There are ingress controllers for kubernetes that support setting up routing rules that would fit your needs. For example, the user's browser could set a header with a desired version and the ingress controller could route the request to a set of containers running that version. There are many other ways to skin this cat (all the way up to complex systems like GraphQL). Pick one that matches the size and complexity of your organization.