As well as updating the dev dependency to hapi v21 here it seems like the types dependency of "@types/hapi__hapi": "^20.0.10" should be removed, since the types are now included with the core library of Hapi since v21: https://github.com/hapijs/hapi/tree/master/lib/types
Would I be able to help by opening a PR to take care of this? Looks like there's a need to cut a new major version of hapi-pino (v12) which will work with Hapi v21 typescript projects.