With 90% of blocks mined with version 0.11.2, the new version now is now required.
Please update to version 0.11.2 as soon as possible if you have not yet.
Wow, that happened pretty quickly.
Yes, unfortunately it happened too quickly. The majority of nodes have not upgraded leaving the 0.11.2.1 users on a shorter chain.
A new release is being prepared where the consensus rule in 0.11.2.1 is disabled to allow 0.11 nodes to get back on the longest chain.
Edit:
Correct chain block 4874191 hash 000000000001d08ec451b8b71be3a8cbe6ad6480da6bc46c600a2d4f537c9172