“It’s important to have several implementations for two reasons: the first is a technical reason. If there is a bad bug in one implementation, if you have another, you can keep the network running.”
Bitcoin ABC developers have also made the codebase for the client Bitcoin ABC 0.17.0 available for download ahead of the launch, with the new consensus rules included. The change is scheduled for May 15 at 12:00:00 UTC and will take place based on Median Time Passed (MTP) instead of at a set block height.