Completed the Bitcoin Cash hard fork, the first invalid block was detected

The hard fork of the Bitcoin Cash network was completed as expected: BitMEX Research has indeed noticed the first block considered invalid by the previous version of the client, as confirmed in a tweet of November 15th.

The Fork Monitor website has found that the 609.136 height block is considered invalid by the Bitcoin ABC 0.19.0 client, while it was accepted by Bitcoin ABC 0.20.6, as proof of the hard fork's success.

The block was undermined by the BTC.com mining pool at 13:44 UTC, with a block size of 0.2 MB and 651 transactions. Previous versions of Bitcoin ABC will now be blocked or will follow a different chain.

Simple changes to the consensus algorithm, but the problems of adapting the difficulty remain

As previously reported by Cointelegraph, the hard fork brought relatively simple changes to the consensus algorithm, which was not thought to cause a split of the chain.

However, the Bitcoin Cash community seems very concerned about the fact that the controversial Difficulty Adjustment Algorithm has not been modified. It updates the difficulty of each BCH block based on the last 144 blocks or, approximately, on the mined blocks in the last 24 hours.

It is feared that some miners are using the algorithm to gain an advantage, causing curious fluctuations in the hash rate and the difficulty.