CometBFT Compatibility modes


There are two different compatibility modes for CometBFT, one for version v0.34 and one for versions v0.37 and v0.38. In order to verify the compatibility used Hermes queries the node's /status endpoint, which contains the CometBFT version used. This can be an issue if a chain uses a custom version which does not output the version string Hermes expects. To still be able to relay for these chains a configuration can be set in Hermes.


The configuration is set per chain and can take two values 0.34 and 0.37, other values will be invalid:

compat_mode = '0.34'

Hermes will act in the following way whether or not the configuration is set:

  • compat_mode is specified and the version queried from /status is the same as the one configured: Use that version without log output
  • compat_mode is specified but the version queried from /status differs: The compatibility mode configured is used, but a warning log is outputted
  • compat_mode is not specified but /status returns a correct version: The compatibility mode retrieved from the endpoint is used
  • compat_mode is not specified and /status does not return a valid version: Hermes stops and outputs an error informing the user that the compat_mode needs to be configured

The configuration can also be found in the example config.toml