This release adds masternodes to the Guncoin network and includes a hard fork to enable payment to those running masternodes. After the hard fork block rewards will be split 47.5% to the miner, 47.5% to the masternode and 5% to the development fund. The hard fork will happen on block 1,277,000 which will happen approximately on the 5th July, please update your client before then.
Guncoin is a multi-wallet release. Most functionality associated with masternodes is currently enabled for the first loaded wallet, however there is multi-wallet support for the masternode RPC functions though these should currently be considered experimental as they have not been thoroughly tested.
To set up and run a Guncoin masternode there's a rough guide to follow on the link below.
Guncoin Masternode Setup Guide
If you find anything that appears to be a bug please create an issue via the GitHub Guncoin Issues page.