What is Happening May 15th?

On May 15th, 2018, the Bitcoin Cash network is scheduled to upgrade the consensus rules. The Bitcoin Cash development community performs periodic and regular network upgrades in order to evolve the network.

Is the New Software Ready Now?

Yes. Bitcoin ABC 0.17.1 is available now, and contains code to run the new consensus rules, as well as code to smoothly transition from the old rules to the new rules at the scheduled activation time.

How does all this affect me? What do I need to do?

If you’re running a Bitcoin Cash node, you should immediately upgrade to Bitcoin ABC 0.17.1 or other compatible software.

What communications efforts are being made so that everyone is aware of the upgrade?

Bitcoin ABC will take steps to contact major exchanges and wallet providers. All assistance in this effort is welcome. You can help by contacting exchanges, wallet providers, and other ecosystem participants, and letting them know they should upgrade their software or run an updated version of Bitcoin ABC or other compatible software.

What changes are in the new software version?

The most notable change is the increase of the maximum blocksize to 32 MB.​

There are also several Bitcoin script operation codes (op codes) being added or reactivated. These include OP_CAT, OP_AND, OP_OR, OP_XOR, OP_DIV, OP_MOD, OP_SPLIT, OP_NUM2BIN, and OP_BIN2NUM. Finally, the OP_RETURN data carrier size increases to 220 bytes.

Are other clients such as Bitcoin Unlimited and Bitcoin XT updating their software?

We cannot speak for other projects but we have seen announcements that they have done so.

When is the Exact Time of the Upgrade?

The upgrade is based on the “Median Time Past” (MTP) method, activating on the MTP time of 1526400000 (Tue May 15 16:00:00 UTC, 2018). In other words, when the median timestamp of the most recent 11 blocks is equal to, or greater than 1526400000, then the new consensus rules shall apply to the next block. The exact time of activation depends on the time this block is found.

Bitcoin ABC is currently testing both the new rules and their activation. A testnet is available. Other groups are encouraged to test as well.