From Bushstar on the Feathercoin forums:

We now have a stable Feathercoin 0.8.5 client for people to use. Thanks to everyone in the community who participated in testing this client. It has been a community effort to get this new release working which is excellent to see. Feathercoin is bigger than any one person and together we are strong.

Please note that you need to upgrade by January 31st as this is when the BDB lock limit rule change takes effect. This is not a hard fork but is in place to prevent such a thing happening unplanned. Remember when Bitcoin unexpectedly forked between 0.7 and 0.8. Well this fix prevents that from happening while we transition.

You can get the new client from the links below.

Windows Wallet

Mac Wallet

Linux Wallets

The source code is available on GitHub from the link below. Please note that the repo for 0.8.5 is not the same as before. The old repo has been renamed to Feathercoin-0.6.4.4 to stop anyone mistakenly downloading the old version.

GitHub Feathercoin-0.8.5

Upgrading

Before upgrading please backup your wallet by going to the File menu in the client and selecting Backup Wallet. Keep a backup somewhere off your computer too. If your hard drive fails you do not want to lose all your coins.

The first time you run the wallet it will update the blockchain to the new format. Please be patient while this process runs.

Windows

Download the installer linked above and then run it. It will uninstall your previous version if you used the installer before and then install the new client. Once installed run as normal and wait while it updates itself.

Mac

Delete the old Feathercoin-Qt application. Download the Mac client Zip file linked above, unzip the archive, go into the unzipped directory and run the Feathercoin-qt client. Once installed run as normal and wait while it updates itself.

Happy Holidays