At 8 am EST, we received the first of multiple reports of users receiving unexpected deposits of Nano into their Binance accounts. We promptly made contact with Binance and recommended they immediately suspend all deposits, withdrawals, and trading until the root cause was identified.

The issue was localized to a small number of nodes that were not upgraded to v17.1, and no double spends occurred on the network. We listed the v17.1 upgrade path as recommended, though more precisely it is a required upgrade, which contains a fix to prevent an issue where transactions could be replayed in rare circumstances. We’re assembling more details for when we’ve confirmed all services have upgraded their nodes to the latest version.

As a part of our release procedure, we notify known services of new node versions, as we did with v17.1. We are working to standardize and improve our method of communicating with services going forward since at the moment this is done in an ad-hoc fashion.

We want to thank Binance and others for their swift action to address this issue.