We've been running a testnet and have executed a number of runtime upgrades. We've also upgraded the node across a variety of changes. New validators are trying to join the network and yet they cannot now run our genesis chainspec.

The network was probably launched around polkadot-v0.9.39 changes.


Error: Service(Other("Error parsing spec file: unknown field phantom, there are no fields at line 175 column 17"))

What's the proper way to debug this and how can we onboard new nodes to our network? It seems we're stuck.

  • This sounds like you are using the JSON chain spec, not the raw chain spec which should be forever compatible.
    – Shawn Tabrizi
    Sep 16, 2023 at 16:49
  • Yea I suspected this, yet running the raw generation on the later node also fails. We will attempt to resolve going back to the OG node.
    – Drew Stone
    Sep 16, 2023 at 17:56
  • Raw generation of an old JSON on new nodes are not guaranteed to work. There could be breaking changes to the JSON format. This is why the raw chain spec exists.
    – Shawn Tabrizi
    Sep 16, 2023 at 18:02

1 Answer 1


Fixed by generating raw chainspec using original node the JSON was created with. Generating raw spec with a newer node doesn't work (and is obviously not guaranteed to work).

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