Upgrading from Tendermint Core

CometBFT was originally forked from Tendermint Core v0.34.24 and subsequently updated in Informal Systems’ public fork of Tendermint Core for v0.34.25 and v0.34.26.

If you already make use of Tendermint Core (either the original Tendermint Core v0.34.24, or Informal Systems’ public fork), you can upgrade to CometBFT v0.34.27 by replacing your dependency in your go.mod file:

go mod edit -replace github.com/tendermint/tendermint=github.com/cometbft/cometbft@v0.34.27

We make use of the original module URL in order to minimize the impact of switching to CometBFT. This is only possible in our v0.34 release series, and we will be switching our module URL to github.com/cometbft/cometbft in the next major release.

Home directory

CometBFT, by default, will consider its home directory in ~/.cometbft from now on instead of ~/.tendermint.

Environment variables

The environment variable prefixes have now changed from TM to CMT. For example, TMHOME or TM_HOME become CMTHOME or CMT_HOME.

We have implemented a fallback check in case TMHOME is still set and CMTHOME is not, but you will start to see a warning message in the logs if the old TMHOME variable is set. This fallback check will be removed entirely in a subsequent major release of CometBFT.

Building CometBFT

If you are building CometBFT from scratch, please note that it must be compiled using Go 1.22 or higher.