There is currently a blockchain fork because gravity well was implemented which changes the difficulty calculation. 
The majority of hashing power needs to upgrade NOW.

**Dear devs, next time you issue a breaking change that is not related to immediate security concerns please ensure it's spaced out 3 months not 12 days.  It's not always easy to upgrade a daemon, many of us have extremely tight security when it comes to changing the daemon out including changing SELinux rules and taking down IDS, updating the binary sig etc.  In my own case it takes 4 hours of intensive effort to change a binary because my systems are that friggin tight.***