In 2017,

• On 21 July BitcoinUnlimited developer Peter Tschipper submitted PR to add a bit of services. This enables nodes to distinguish between BTC nodes and BCH nodes during communication.

• On July 22, BU developer FreeTrader submitted code for BitcoinABC to do the same.

• On August 3rd UTC, BitcoinCore developer Matt Corallo submitted a PR to BitCoincoinore, which disconnects from each other when it detects that each other is a BCH (in terms of services bits).

• On August 3rd UTC Matt Corallo sent the PR above and immediately sent an issue to BitcoinABC asking BCH to change the Netwrok Magic Number to better isolate THE BTC and BCH nodes.

• On August 4 UTC FloweeTheHub developer Tom Zander documented a discussion among BCH developers on the Linux mailing list about resolving network fragmentation by changing the Network Magic Number. The proposal was mentioned by Deadalnix (Amaury Sechet).