Bitcoin - BIP91 / Segwit / Hard Fork - "Official" Discussion Thread


Jun 21, 2011
Lets have a thread to discuss / panic the upcoming events with Bitcoin.

Countdown "clock":
As of 10:40am EST: 255 blocks until rejecting non-SegWit blocks.

What this sit shows is how many blocks are being sent over with the "signal" of the new standard, which is to be BIP91. Currently 95%+ of all blocks are coming out as this, which by calculation/speculation means that others will start being rejected in 255 blocks (and dropping).

From this article:

But, the lock-in is just the first step to activating SegWit on the network, and other steps come with a bit more complexity.
Specifically, the following things need to happen for it to activate:

    • There will be a 336-block "grace period," taking about two and a half days, during which miners have time to prepare for activation.
    • BIP 91 will activate at block 477,120. Theoretically, mining pools will start rejecting blocks that do not signal support for SegWit (BIP 141). In this way, BIP 91 is a "coordination mechanism" that gets other mining pools to follow along or lose out on mining rewards.
    • SegWit could lock-in during the next difficulty adjustment period of 2016 blocks, which takes about two weeks.

The latter is when Segwit activation is "all in the clear," as BIP 91 creator James Hilliard put it.

That's when bitcoin's SegWit upgrade will be official, and an upcoming user-activated soft fork (UASF) proposal, BIP 148, superseded.

Letter from Coinbase regarding their plans:

Dear Coinbase Customer,

We are contacting you to make you aware of recent developments in a number of proposals for technical changes to Bitcoin. All BTC stored on Coinbase will remain safe during these events described below.

The User Activated Hard Fork (UAHF) is a proposal to increase the Bitcoin block size scheduled to activate on August 1. The UAHF is incompatible with the current Bitcoin ruleset and will create a separate blockchain. Should UAHF activate on August 1, Coinbase will not support the new blockchain or its associated coin.

The User Activated Soft Fork (UASF) is a proposal to adopt Segregated Witness on the Bitcoin blockchain and could result in network instability. It is scheduled to activate at the same time as the UAHF.

To ensure the safety of customers’ funds, we will temporarily suspend BTC deposits, withdrawals, and buy/sell starting approximately 4 hours before activation of either fork.

    • If you do not wish to have access to UAHF coins, and do not wish to access your BTC during the fork, you are not required to take any action.
    • If you do wish to have access to UAHF coins or access your BTC during the fork, you should send your BTC from Coinbase to your external address by July 31.
For more information on these potential Bitcoin forks, please refer to this article:

Thank you,

Coinbase Team
Check out our Status Page and Twitter for the latest updates from Coinbase.

Its looks like this is happening.

Edit: According to this thread, maybe not:

Soft-forks are ultimately enforced by users, not miners, and right now practically no users are running BIP-91 enforcing nodes like segsignal. So a majority of miners can reneg on BIP-91, fail to activate segwit, and get away without any long-term¹ consequences because the BIP-91 invalid blocks they would be producing are considered to be perfectly valid by the vast majority of users' nodes.

Will this happen? It's notable that even though BIP-91 just activated - something which is supposed to signal clear intent to activate segwit - a bit less than a majority of miners are actually signaling segwit. While no smoking gun, it's a sign that we may be in a situation where a majority of miners do not intend to actually activate segwit.

I don't think this is the most likely outcome - there's other pressures like social that probably would serve to enforce BIP-91 - but I'd give it significant odds of happening. Maybe 25%?

The reason why I think it's as high a chance as 25% is because there's a few ways to reneg on segwit with plausible deniability. For instance, miners could "accidentally" mine a bunch of BIP-91 invalid blocks - e.g. claiming it was due to validationless spy-mining - and then decide not to reorg out those blocks. At that point, the BIP-91 rules have been broken, but lots of transactions depend on them, so the whole thing gets called off with vague mutterings of "we'll try again once we upgrade our systems" or "well obviously soft-forks are just too dangerous!"

1) In the short-term reneging on BIP-91 could lead to a large reorg - why I recommend that people be very cautious about trusting confirmations until segwit is fully activated in (hopefully) a few weeks. It's quite plausible that we'll see even 6+ confirmed transactions get double-spent due to reorgs. Now, that doesn't mean it's likely, but if a double-spent transaction would be a devastating loss, you should be very cautious. Of course, often a double-spend isn't devastating: if I'm selling a house I know who is buying it, a double-spend will land them in jail, so I'm not relying solely on Bitcoin confirmations to protect me.

A user linked these timelines, not sure source:

2017 July 23 18:00 GMT — BIP91 epoch finishes, BIP91 is activated
2017 July 23 18:00 GMT onward — Every block signals BIP141 (Segwit)
2017 July 27 or thereabouts — New Difficulty Adjustment Period Begins (2016 blocks). Every block will be signaling for Segwit.
2017 August 1 00:00 GMT — BIP148 starts, but does nothing since every block is signaling BIP141 due to BIP91.
2017 August 10 or thereabouts — Difficulty Adjustment Period closes with >95% signaling and BIP141 locks-in.
2017 August 23 or thereabouts — Difficulty Adjustment Period closes and BIP141 (Segwit) is active.
2017 November 18 or thereabouts — 2x Hard Fork (scheduled)


The question is, then what? Skyrocketing prices? falling?

Are you buying in now?
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Jun 21, 2011
BIP91 Reached

"Well i'm stupid and still confused, whats going on?" Guess what, I'm just as confused! I made this thread, that none of you assholes have bothered to reply to, to try to clarify it! Fuck!

Here's a somewhat simple answer:

Guys, now that BIP91 is active. Do we still have a chance do see segwit2x? Miners now have to choose between BIP 141 or segwit2x? Can someone clarify that do me please? ps: i dont wan't segwit2x to happen

The Segwit2x uses BIP141 to activate Segwit and in aprox. three months hard forks to double base block size.

BIP141 should enable Segwit in 4 weeks.

Segwit2x software should create a hard fork 144*90 blocks after Segwit is active (sometime around November)

Thing is, not everyone is running Segwit2x (btc1) software. The rest of the implementations will not follow that fork so we may end up with a Segwit coin and a Segwit2x coin sometime in November


Coinbase tweet and post, they will not support a UAHF (User Activated Hard Fork):

Do I need to withdraw my BTC from Coinbase?
The UAHF will functionally create two different versions of Bitcoin. In contrast, the UASF will likely not create another version of Bitcoin. However, the UASF may initially cause instability on the Bitcoin network. To ensure the safety of customers’ funds, we will temporarily suspend BTC deposits, withdrawals, and buy/sell starting approximately 4 hours before activation of either fork. If:

(a) you wish to access your coins on the UAHF chain, or
(b) you want to ensure you can access your funds immediately while the UAHF/UASF forks are happening,

you should withdraw your BTC from Coinbase to an external wallet address under your control by July 31.

This reads to me like Coinbase is intending on keeping any split/forked coins that might be created after the fork, instead of giving them to you and your wallet.

Here's a FAQ on storing your coins:

This comes from this thread on bitcoin reddit:
TLDR; If you do not move your money to a wallet you control, you WILL (unless BCC goes to absolute $0 after Aug 1st) lose money.

Then there's these people, who are planning to match bitcoin wallets with a new coin:

Bitcoin Cash Announcement:

On August 1st 2017, We the People will breathe new life into Bitcoin.

A group of miners, developers, investors, and bitcoin users will upgrade the Bitcoin protocol as specified by the User Activated Hard Fork (UAHF).

Those who do not want to follow our lead are free to use whichever chain they like. Miners implementing the UAHF will safely split away, creating a new version of Bitcoin called "Bitcoin Cash".

All current Bitcoin holders will automatically own Bitcoin Cash. The existing ledger at the time of the split is preserved, thus users retain any balances they had before the split.

Bitcoin Cash brings sound money to the world. Merchants and users are empowered with low fees and reliable confirmations. The future shines brightly with unrestricted growth, global adoption, permissionless innovation, and decentralized development.

These ideals can be achieved, but it depends on you to succeed. We need the support of miners, investors, and users like you. Join us to help achieve Satoshi's original vision of Bitcoin as Peer-to-Peer Electronic Cash.

Commentary on Bitcoin Cash:

Apparently these guys are a scam of sorts, trying to lock in people's coins to which they hold and profit off of while they hope their version of the coin pans out. Or if you trade your BCC, they can do a replay attack on your real BTC using similar/same hash values / private key. I think, I dunno. Its confusing.


Goldman Sachs on Bitcoin Prices, going to hit ~$3,700:

In a report posted overnight by Goldman's chief technician Sheba Jafari, she writes that since "Bitcoin is still within the limits of a well-defined range, it may need another few swing within the range before resuming its underlying trend" higher. Eventually, after some potential volatility that could send it as low as $1,786 "but not much further from there", Goldman expects the original cryptocurrency to surge to a "minimum target at 2,988 and scope to reach 3,691."


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Oct 8, 2010
If all you have right now is alt coins, is it recommended to keep those or trade them for BTC and keep that?

BTC is where it was a month ago, but alt coins are down 20-50% in that same time frame, so they've not been very synchronous. Not sure what to do.


Fully [H]
Apr 11, 2007
I'm looking for a BTC wallet that doesn't require 150 GB of data be downloaded. Does such a thing exist?