Release 4.2.0 - (March 16, 2022)

• The minimum python version was increased to 3.8 (#7661)
• Lightning:
  • redesigned MPP splitting algorithm (#7202)
  • trampoline: implement multi-trampoline MPP (#7623)
  • implement option_shutdown_anysegwit, and allow dust limits below 546 sat (#7542)
  • implement option_channel_type (#7636)
  • implement modern closing negotiation (#7586, #7680)
• improve support for "lightning:" URIs on all platforms (#7301)
• Qt GUI:
  • add setting "show amounts with msat precision" (5891e039)
  • add setting "add thousand separators to bitcoin amounts" (#7427)
• CLI/RPC:
  • implement Unix sockets and make them the default (#7545, #7566)
  • add "bumpfee" command (#7438)
• Kivy GUI:
  • show network setup on first start before wallet creation (#7464)
  • add "Child Pays For Parent" option (#7487)
  • improved locale handling (22bb52d5, 7cb11ced, 4293d6ec)
• Hardware wallets:
  • trezor: bump trezorlib to 0.13 (#7590)
  • bitbox02: bump bitbox02 to 6.0, support send-to-taproot (#7693)
  • ledger: support "Ledger Nano S Plus" (#7692)
• Library:
  • added support for sighash types beside "ALL" (#7453)
  • signmessage: also accept Trezor-type sigs for segwit addrs (#7668)
  • network: make request timeout configurable (#7696)
  • paytomany (onchain txout batching) now allows multiple max("!") amounts with specified weights (#7492)
• Binary builds
  • AppImage: changed base image from ubuntu 16.04 to 18.04 (5d0aa63a)
• migrated from Travis CI to Cirrus CI (#7431)
• Lots of other minor bugfixes and usability improvements.