TRPC v10 to v11 upgrade procedure

[jludwiggreenaction]

Hello,

I have reviewed the migration guide and haven't seen this specifically called out anywhere: were there breaking changes to the RPC spec when moving from v10 to v11? As in, if I deploy my v11 server, will existing clients still deployed with v10 immediately break?

Appreciate any insight you can share, thanks.

[tejasae-afk]

Yes, v10 clients will break against a v11 server. tRPC v11 changed the HTTP call spec, specifically how batching works and the endpoint shape, so the wire protocol is not backwards compatible.

The migration guide covers this but does not call it out explicitly. The expectation is a coordinated deploy of server and client together.

If you need a rolling upgrade window, you can run a v10-compatible adapter alongside v11 temporarily, but that is not officially documented as a long-term strategy. Simplest path is just deploying both at the same time.

[jludwiggreenaction]

Thanks for the reply. Would you able to clarify one more thing about this as well:

If you need a rolling upgrade window, you can run a v10-compatible adapter alongside v11 temporarily

By adapter, do you mean something that exists in TRPC (e.g. similar to the fastify adapter), or are you just referring to running my own custom logic for that?

Appreciate your help with this

[Nick-Lucas]

I believe the account you're replying to may be an AI agent. But you should try mixing versions and see if anything you're doing breaks. If version tear is really a problem then you could run a frozen v10 API instance for old clients until you're ready to cut over entirely.

[jludwiggreenaction]

I believe the account you're replying to may be an AI agent. But you should try mixing versions and see if anything you're doing breaks. If version tear is really a problem then you could run a frozen v10 API instance for old clients until you're ready to cut over entirely.

Thanks, will do. I should've known it was a bot since this thread was so old 😭

[tejasae-afk]

Hey, No I just used gpt to rewrite that's all. And was searching for issues when then I came across this one.