Deserialise failure when connecting to FC4 node

[coot]

I downloaded FC4 release of Deadalus and run:

cabal run exe:cardano-cli -- get-tip --config ~/.local/share/Daedalus/mainnet_flight/config.yaml --socket-path ~/.local/share/Daedalus/mainnet_flight/cardano-node.socket

from IntersectMBO/cardano-node@0172a96

The client application returned:

MuxError {errorType = MuxBearerClosed, errorMsg = "<socket: 11> closed when reading data, waiting on next header True", errorStack = []}

The logs of the node reveal more detail:

[fozzie:cardano.node.LocalErrorPolicy:Error:44] [2020-04-18 07:35:57.80 UTC] {"event":"ErrorPolicyUnhandledApplicationException (DeserialiseFailure 12 \"decode NodeToClientVersion: unknown tag\")","kind":"ErrorPolicyTrace","address":"LocalAddress {getFilePath = \"\"}"}

It's likely that the introduction of LocalStateQuery in #1507 wasn't actually backward compatible.

[coot]

The problem is in the decoder. It should not fail if the version number is not recognized.