BTC testnet4 support

[jlopp]

FYI testnet3 is being deprecated; you can find the parameters for testnet4 here: bitcoin/bitcoin#29775

[cculianu]

Ah thanks for the heads-up. Yeah we in BCH also deprecated our testnet3 and are onto testnet4. Good to see the BTC people are doing similar. I'll look at their changes and add BTC testnet4 soon, if they didn't do anything crazy ...

[cculianu]

Oh ok I just noticed they haven't merged this yet but it looks essentially very compatible with existing testnet3, so it should be no problem to add support for this to Fulcrum. I will do so as soon as they merge this and/or plan a release containing it.

Thanks again for the heads-up. I will leave this issue open to remind myself to indeed add this to Fulcrum.

[jlopp]

Yeah it's not finalized yet but I think it's pretty close.

[cculianu]

Sounds good I’m traveling now but I’ll add support once I get back and have it ready for once they merge. Good stuff again thanks for the heads up!