[castorp]

You need to use pg_dump from the new version, not from the old version.

[jasfi]

I think you found a common stumbling block. The tutorial people follow may say to run pg_dump and many people would assume you're running it from the old version.

[rapind]

Wait, what? Explain please.

OK upon further thought, what you're saying is to use the pg_dump tool that comes with the pg version you are upgrading to.

I read it as "use pg_dump instead of pg_restore"...

[mh-]

Yes. Put concisely: Use the client tools from the newest version involved for all steps.

[autra]

Yes, and usually, it means you need to use the full binary path unfortunately (because debian wrappers embedded in the package select the version from your 5432 cluster).