Difficulty Freeze

From CryptoCurrency Wiki

"The difficulty Freeze is an alternative to the Difficulty Bomb that is implemented within the protocols difficulty adjustment algorithm. The Difficulty Freeze begins at a certain block height, determined in advance, and freezes the difficulty. This does not stop the chain, but it incentivizes devs to upgrade at a regular cadence and requires any chain split to address the difficulty freeze.

The difficulty Freeze is a mechanism that is easy to predict and model, and the pressures of missing it are more readily felt by the core developers and client maintainers. The client maintainers are also positioned as the group that is most able to respond to an incoming Difficulty Freeze."