v0.9.1: The Antiguan BTC Maximalist Society

We're pleased to announce the 0.9.1 release of c-lightning, named by Jon Griffiths. This is a significant release with major bugfixes to multi-part payments and various notable speedups and improvements across the board. **Did you know**: c-lightning deprecates features with 6 months warning, and you can set `allow-deprecated-apis=false` to test? ## Highlights for Users * The sending of multi-part payments has seen a lot of work, covering more corner cases and generally becoming much more robust. * New official plugins create commands `multiwithdraw` and `multifundchannel` to easily produce a single transaction which does more than one thing; these use the PSBT plumbing created for v0.9.0. * We produce far less log spam when log-level is set to `debug`, so if you've avoided setting that before, I recommend trying now. * Startup checks that bitcoind is the correct version, and relays transactions * Builtin plugins are now nominated as *important*, and you can nominate others as important too. The daemon will stop if these fail. * You can now build a postgres-only installation, without sqlite3. ## Highlights for the Network * Our invoices now supply more than one routehint if we think you'll need to use multi-part-payments. * We prune channels which are not updated in both directions every 2 weeks. * Our default CTLV expiry has increased to 34 blocks, or 18 if we're the final node, as per updated specification recommendations (https://github.com/lightningnetwork/lightning-rfc/pull/785) ## Highlights for Developers * PSBT APIs fleshed out with `utxopsbt` and locktime arguments. * Plugins can easily mark commands and options deprecated. * The new `channel_state_changed` notification lets plugins easily track channel behavior. More details can be found at https://github.com/ElementsProject/lightning/blob/v0.9.1/CHANGELOG.md Thanks to everyone for their contributions and bug reports; please keep them coming. Since 0.9.0, we've had 391 commits commits from 15 different authors. A special thanks goes to the 3 first time contributors: * Matt Whitlock @whitslack * Sergi Delgado Segura @sr-gi * Moller40 @Moller40 Cheers, Christian, Rusty, ZmnSCPxj, and Lisa