I got similar message from SONM slack yesterday and today got another message from MONACO slack but body of this message looks quite different.
@slackbot View in the archives
slackbot 8:30 PM, July 12th
@m-ico asked me to remind you “=== URGENT ANNOUNCEMENT ===
Please be advised that we are experiencing some errors with the Monaco (MCO) tokens smart contract.
We decided that the best way to solve the problem is to fork the Smart Contract.
It was a simple process and everything worked out without issues.
We implemented a seamless procedure to update the smart contract
using an automatic process through MyEtherWallet services.
Please use the link below to unlock your wallet through MyEtherWallet
and follow the instructions on their website.
https://myetherwallet.com#update-token-contract-682938 Failure to do so may result in loss of Monaco (MCO) tokens.
Thank you for your cooperation and understanding.
https://mona.co © 2017 Monaco Technology GmbH”.
I suggest everyone to remain alert about these types of scam attempts going on slack channel of every projects right now. Don't click any link posted on slack channels.