SN-2455 已核对来源，附原文与上下文。
看来我们在 74689 附近反超了坏链。0.3.9 及更低版本的节点过去几个小时里返回的都已经是当前区块号了。
It looks like we overtook the bad chain somewhere around 74689. 0.3.9 and lower nodes have been responding with the current block number for some hours now.
也就是说，升级前不再需要删 blk*.dat 了。直接升级就行，它会自动重组掉坏区块链。
That means it's no longer necessary to delete blk*.dat before upgrading. You can just upgrade and it'll reorg away the bad block chain.
感谢大家的快速响应！
Thanks to everyone for the quick response!
