On November 15 2018, the Bitcoin Cash (BCH) network successfully upgraded as part of the planned feature changes outlined in the November Upgrade Specification.

Here are some of the highlights from the upgrade:

  • Remove topological transaction order constraint, and enforce canonical transaction order (also called “CTOR”)
  • Enable OP_CHECKDATASIG and OP_CHECKDATASIGVERIFY opcodes
  • Enforce minimum transaction size
  • Enforce "push only" rule for scriptSig
  • Enforce "clean stack" rule
  • Automatic replay protection for future upgrades

The two most exciting changes of the upgrade are CTOR and OP_CHECKDATASIGVERIFY:

CTOR which is part of the comprehensive technical roadmap allows for faster transaction ordering and block propagation. This feature helps scale Bitcoin Cash for the world.
OP_CHECKDATASIGVERIFY which is also part of the roadmap, is a feature that allows a transaction to verify that it has been supplied with a valid signature and message. This will enable new applications to be built on the Bitcoin Cash network that weren’t possible before. Please see op_checkdatasig.md for additional details.

Frequently Asked Questions

When was the upgrade completed?

On block 556767 the upgrade was activated (Epoch 1542300000). As of this writing, there has been well over 300 blocks mined since the activation with Bitcoin Cash (BCH) having the most accumulated proof of work blockchain.

Was there a fork when the upgrade happened?

There are some who chose to run different software instead of what was proposed in the upgrade. Anyone that runs different software technically “forked.”

What is a checkpoint?

For the upgrade, there was a remote possibility that a malicious entity may have tried to attack the chain with deep reorgs. In order to safely prevent this attack, we updated checkpoints which were first used by Satoshi Nakamoto to the current fork height + 180 blocks to thwart any attempt at blockchain reorgs and attacks. Checkpoints have been used in every past Bitcoin Cash network upgrade including this November 15 upgrade.

When in the next network upgrade supposed to happen?

Next scheduled upgrade will take place on May 15, 2019.