@jgarzik jgarzik released this Jul 1, 2017 · 50 commits to segwit2x since this release

Assets 16

btc1 Core version 1.14.3 is now available from:

This is a beta version release, including various bugfixes and
consensus changes.

Please report bugs using the issue tracker at github:


btc1 Core is extensively tested on multiple operating systems using
the Linux kernel, macOS 10.8+, and Windows Vista and later.

Microsoft ended support for Windows XP on April 8th, 2014,
No attempt is made to prevent installing or running the software on Windows XP, you
can still do so at your own risk but be aware that there are known instabilities and issues.
Please do not report issues about Windows XP to the issue tracker.

btc1 Core should also work on most other Unix-like systems but is not
frequently tested on them.

Release notes and comments for version 1.14.3, aka "the beta release"

Expectation Setting

The charter and goal of the segwit2x effort has always been tightly
focused on a "SegWit + 2M HF" safe network upgrade, and
producing/testing/auditing software to accomplish that. Milestones
are intentionally labeled "alpha" or "beta" per normal software
engineering practices, and expectations should be set accordingly.

For this beta release, we can expect that network and consensus
protocols meet the design goals, but may be tweaked based on field
testing and feedback from the general public. Bugs are an expected
part of the public beta testing process.

Consensus Rule Overview

The over-simplified summary of the network upgrade sequence is:
bit-4 SegWit activation + 144*90 blocks

This matches the goal outlined in the kickoff Project Mission: "Segwit
will start being enforced shortly after lock in, whereas as 2mb blocks
will be a bit farther out to ensure people have plenty of time to
upgrade their nodes."

Consensus Rule changes

Two issues addressed in this release relate to consensus,

  1. Some housecleaning, removing an expired rule. Issue

  2. Hard Fork on Block X. Issue #29

This change tightens the predictability of the network upgrade. The
traditional approach is a two-step sequence of (1) rules change, and
(2) zero or [many] more blocks later, a large block is mined. This
release requires a large block - greater than 1M - precisely at rule
change time. Although the primary motivation is predictability, an
additional motivation is wipeout protection.

See the github issue for additional background and discussion.

Consensus Rule review phase

From the standpoint of the segwit2x charter, the software matches the
two points of the NYA agreement. No further rule changes are

This is the best phase for wider public review of both the consensus
rule changes, as well as the software changes themselves. "Given
enough eyeballs, all bugs are shallow." Feedback is actively
solicited and considered.


Now that the core rule changes and activation are frozen (pending
community review), the next step is wider review and testing by the
working group and general public as mentioned.

To assist that process, specifications will be drafted in unnumbered,
IETF draft-style form at

Multiple BIPs will be produced very soon, documenting the segwit2x
changes. These drafts will be PRd to after a wider round of feedback from
the specs posted at /specifications

Testnet test plan

In addition to individual WG members and developers who have been
testing (thanks!), a sub-team inside the working group has been
auditing bitcoin libraries/stacks/apps as well as helping test plans
and test scenarios.

The public testnet5 will be taken through several test scenarios, and
some of these activations will be baked into updates of the btc1