Hey Steemians,
Here I simply tell you what a Hardfork is.
HARDFORK
Each coin has a protocol / software. Assumed in the blockchain is a block 2 MB in size. The new protocol says that from now on a block should be 20 MB.
A Hard Fork will find a block (call it X) that will be discarded by the older version but accepted by the newer version. From this block X, two blockchains develop in parallel.