The Grin project has already successfully hard forked once already earlier this year with a change in the C29 PoW algorithm from Cuckaroo29 to Cuckarood29 and now a second hard fork has been planned. Grin’s Hard Fork 2 is planned for block 524160 that should be reached sometime in January next year (around the middle of the month) with the testnet expected to fork a month earlier. Compatible versions of grin node, grin-wallet, and grin-miner will be versioned 3.0.0 or greater with the first releases of these are scheduled for December.
Grin remains true to its commitment to tweak CuckARoo as part of every network upgrade it does in order to discourage manufacturers from building specialized ASIC mining hardware for it, ASICs on th other hand are encouraged and being developed for the other algorithm C31 that Grin uses. As such, the currently used algorithm Cuckarood29 will be deprecated for a new algorithm, though its details are yet to be announced. This means that if you want to be able to continue mining Grin with the C29 algorithm after mid-January next year after the fork happens you would need to update your miner software to support the new algorithm. The first beta binaries of the software should be available in the next couple of days along with details about the new algorithm, so miner software developers will have enough time to integrate the required changes for the new algorithm by the time the hard fork executes.