Dogecoin Client 1.5.1 has been released, here is the info from the official post on reddit.  They recommend backing up your wallet before trying to upgrade, just in case:

Downloads:

Windows Installer
Windows Archive
Mac OS X App

Release highlights:
- Switched to Boost 1.55 to fix network connectivity issues on Windows
- Removal of reliance on IRC for discovering nodes
- Support for URL protocol, eg. dogecoin:addr?amount=xxx&(see Bitcoin’s implementation)
- Ability to automatically look up transactions on Dogechain from your client
- Working Windows setup script and installer
- Opt-in debug logging via -debuglog (to save disk space and stop constant writing)
- Fixed Mac Splashscreen’s greedy desktop behavior
- Reimplemented testnet, fixing RPC crash due to no genesis block being present
- Allow user to load any wallet from data directory specified using -wallet=mywallet.dat
- Updated to LevelDB 1.15 to address blockchain database corruption issues
- Allow user to send change only to specified address(es) using -change= (one -change parameter per address)
- Fixed RPC difficulty look up

Go here for the official post and for help with troubleshooting.