[Denvercoder9]

So yes, in theory you can always deploys sets of compatible services, but it's not really workable in practice: you either need to deploy the world on every change, or you need to have complicated logic to determine which services are compatible with which deployment sets of other services.

There's a bigger problem though: in practice there's almost always a client that you don't control, and can't switch along with your services, e.g. an old frontend loaded by a user's browser.

[nkmnz]

The notion of external clients is a smell. If that’s the case, you need a compat layer between that client and your entrypoints, otherwise you’ll have a very hard time evolving anything. In practice, this can include providing frontend assets under previously cached endpoints; a version endpoint that triggers cache busting; a load balancer routing to a legacy version for a grace period… sadly, there‘s no free lunch here.