It's important to keep on top of wallet updates when operating nixd on a VPS. Wallet updates are often mandatory, but are usually released with a grace period of several days before the operator is required to update.
Important - if a wallet is not updated by the specified block, the node can become detached from the longest chain and a re-sync will be required. In this scenario, any resulting rewards/fees received on the forked chain are worthless.
Manual updating
Log into your VPS and use wget to download the latest version:
If you used the auto-installer script from CryptoSharks, you'll need to use his auto-updater to bring your VPS up to date with the latest version. The update script itself needs to get updated so wait until it's ready.