Today, November 24, 2019, marks the official release of Bitcoin Core 0.19.0[1], the 19th major release of Bitcoin’s original software client launched by Satoshi Nakamoto almost 11 years ago and still the dominant Bitcoin implementation on the network today. (Though due to an issue that came to light in a late stage of the Bitcoin Core 0.19.0 release process, the version released for download is actually 0.19.0.1.) Overseen by Bitcoin Core[2] lead maintainer Wladimir van der Laan, this latest major release was developed by over a hundred contributors over a span of about six months.
The result of 550 merged pull requests, Bitcoin Core 0.19.0 includes a range of performance improvements, modernizations and bug fixes, as well as other changes.
Here’s an overview of some of these changes.
Bech32 Addresses by Default in the GUI
The “bech32” address format (BIP 173[3]) had already been introduced in Bitcoin Core 0.16.0[4], released in early 2018, but is now for the first time set as the default option in the Bitcoin Core wallet Graphical User Interface (GUI).
Bech32 addresses are the addresses starting with “bc1” (as opposed to addresses starting with a 1 or a 3.) These addresses are also a bit longer, but use fewer different characters than the current address format, as there is no longer a distinction between lowercase and capital letters. (This reduces the potential for human mistakes, for example, when an address is read out loud.) Bech32 addresses are also designed to limit mistakes caused by typos.
Additionally, bech32 offers benefits in the context of SegWit. Some wallets that offer SegWit — including the Bitcoin Core wallet by default up until now — do so by “wrapping” it into P2SH outputs (with addresses starting with a
