The final release of Tendermint KMS v0.6.0 is out 
https://crates.io/crates/tmkms/0.6.0
We are now running this release in production here at @iqlusion without issues.
The main changes from v0.6.0-rc1 are some logging improvements including more information about the height/round/step of blocks being signed, as well as their block IDs, which is useful for understanding the operation of multiple concurrent validators operating on the same network simultaneously.
Full changelog available here: https://github.com/tendermint/kms/pull/329