Users that are still running older versions of Zcash (in particular, <= 1.0.3) are at high risk of a blockchain fork or stalling event that could open them up to double-spending attacks. All users and miners are encouraged to update their Zcash clients to the latest version and to reindex if they are experiencing problems. Most miners have updated to the most recent version of Zcash, and there is no evidence of a persistent chain fork affecting updated clients.