Prior to the Grin network launching in January 2019, the development team committed to four hard forks within the first two years. This hard fork schedule is largely in place to ensure that the hash rate share does not become overly centralized due to ASICs. Grin has employed a dual proof-of-work model with one ASIC friendly algorithm and one ASIC resistant algorithm. Wednesday’s hard fork was successfully executed to prevent ASICs being built for the ASIC resistant algorithm.
Source: CoinDesk