"A group" here means people runs BCH nodes and mines BCH?
such changes however will require a high amount of support. so a "group" in this context can not be a couple of miners who have 1% of the total hashrate. which is also why "bitcoin" defines these hashrate support thresholds for each fork (>95%).
Thanks for the answer. But you said "these hashrate support thresholds for each fork (>95%)". BCH splitted into BSV and BCHABC, I think it's impossible to reach 95% for each fork. Right? If BCH fork only BSV or BCHABC, hashrate support thresholds should be over 95%. this I can understand. But there are 2 forks. I think hashrate of 2 new forks will be keep at a value as long as 51% attack cannot happen. Correct for me if Im wrong.
the 95% that i mentioned is for when you want to improve the system with a hard fork to to create a useless altcoin that nobody wants. bitcoin is designed to be decentralized and that means the whole network or at least the majority (95%) has to agree with the rules that we call "consensus rules". when you fork with less than that, it means you don't have the majority's support. for example bitcoin had forks before. a hard fork in early days to fix an overflow bug, another fork a couple of years later to add P2SH scripts and the soft fork of last year to add Segregated Witness. all done with that high support which is why bitcoin is working well and decentralized.
technically you can create a fork with your own PC, you don't even need any ASICs, you just use your CPU to mine a block but you have to change the difficulty and how it works for the fork to work. then build on top of it to have a new blockchain. but that blockchain (that new coin) will be only used by you alone.
that is what happened with bitcoin cash fork last year in August and it happened now with a fork of this fork again to create a copy of copy coin!
as for their hashrate, there is currently a war between these altcoins over it and there may even be some 51% attacks on each other. because they lack that support i talked about and they started this trend themselves when they forked from bitcoin last year with that little support they had!