https://www.dash.org/forum/threads/announcing-dip-8-chainlocks.42304/#post-203093
We're excited to announce the release of DIP 8, which details a mechanism for mitigating 51% mining attacks on the Dash blockchain. This protection mechanism, called ChainLocks, builds upon the Long Living Masternode Quorum (LLMQ) system established by DIPs 6 and 7.
You can read the details about DIP 8 on GitHub or a less-technical overview of DIP 8 titled Mitigating 51% attacks with LLMQ-based ChainLocks on the Dash blog.