BIP 91 Locks In

After a long drawn out Bitcoin scaling debate, or what some would label as more of an ordeal, BIP 91 has officially locked in.

The BIP 91, or Bitcoin Improvement Protocol 91, was an attempt to stave off some of the more aggressive scaling options and offer a compromise of sorts in activating SegWit (Segregated Witnesses) now and adding support for 2 MB blocks later, which is now set for November.

By signaling support for BIP 91, mining pools (which have mined 93.1% of all blocks during the last 24 hours with the BIP 91 flag set) stood united behind the proposal which was designed to avoid a potential bitcoin split (fork) in the network.

As expected with the news, Bitcoin saw a rise in its price as it got closer to the lock in point, however it has recently declined again as undoubtedly some profit taking is occurring.

The BIP 91 lock-in is the first step to actually activating SegWit on the network. The remaining steps still required for it to activate include:

• There is a 336-block “grace period”, which will take about two and a half days to complete (based on 10 minute blocks), during which time miners will need to upgrade their nodes to be BIP 141 compliant. Blocks not signalling BIP 141 (bit 1) after this time will be rejected.
• BIP 91 will officially activate at block 477,120. At this point mining pools will start rejecting blocks that do not signal support for SegWit (BIP 141).
• SegWit is then scheduled to lock-in during the next difficulty adjustment period, which will take another 2016 blocks, or about two weeks.

This last milestone is when activation of the SegWit upgrade will be considered official.

There is still some concern in the community about the time in between when BIP 91 is activated and SegWit locks in. Some of it revolves around thinking some miners may be fake signaling and stop before SegWit locks in. Other thoughts concern if pools are using the correct version of software that enforces the bit and not simply provide the signaling, This enforcement portion is what will provide teeth to the proposal by blocking blocks not supporting BIP 141.

I am personally happy to see some sort of resolution moving forward to this long standing question that was hanging over Bitcoin’s future. While we are not in the clear quite yet, the road is becoming a bit less bumpy and the paved highway is now within site just off the horizon.