⛓️‍💥 Chain Split Over a BerkeleyDB Lock Limit

On 11 March 2013, block 225430, mined on version 0.8.0, exceeded BerkeleyDB's 10,000-lock limit and split the network into two chains for six hours. Bitcoin.org: "A bitcoin miner running version 0.8.0 created a large block... that is incompatible with earlier versions of Bitcoin." Pools on 0.8.0 downgraded to 0.7; the chain reunified at block 225454, and 0.8.1 removed the limit.