# tRPC 10 with Next 13 App dir
Cannot read properties of undefined (reading '__untypedClient') on trpc.Provider
🙋♂️ help wanted👻 invalid🔎 needs more investigation/info⏮ needs reproduction🐛 bug: unconfirmed
Potential for future type error in TRPCError & TRPCClientError
@trpc/server@trpc/client🔎 needs more investigation/info
Upgrade tRPC from 9.12.0 to 9.12.2 breaks my existing code
🔎 needs more investigation/info