After investigating the issue mentioned in the last update: https://www.mwc.mw/mimble-wimble-coin-articles/critical-issue-in-mwc-blockchain-will-update-with-required-actions
It appears that this was a false alarm. While one of our nodes that was running in full chain validation mode reported an error, it turns out that error was unrelated to consensus and that it was just due to a disk i/o error that was causing the problem which appeared at first to be more critical.
One thing that came out of this is that more of the network should be running with chain_validation_mode set to true. In particular large miners should update their mwc-server.toml file with the following line:
chain_validation_mode = "EveryBlock"
We have updated our seed nodes to do full validation on every block. We may make this setting the default on a future full node release. Sorry for the false alarm and any miscommunication regarding this issue.