Who needs to upgrade?

All operators of a Bitcoin ABC full node must upgrade to the latest major version (0.27.x). This includes Avalanche staking nodes, Miners and Exchanges. The up-to-date node version is available at our Releases page.

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Exactly when will the upgrade activate?

In order to activate reliably at a predictable time, the network upgrade uses the "Median Time Past" mechanism. The upgrade activates when the median of the last 11 blocks reaches timestamp 1684152000 (12:00:00 UTC on May 15th, 2023). This means that the upgrade doesn't actually activate exactly at that time, but typically about one hour later, when 6 blocks with timestamps greater than the activation time have been produced.

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What features are included in the Network Upgrade?

Consensus-enforced transaction version

The version field of eCash transactions will be restricted to versions 1 or 2 by the consensus rules. This means that blocks containing a transaction with a different version number can no longer be mined. The purpose of this change is to pave the way for future implementation of a new transaction format. It will allow the new transaction format to use a version number that has never been used before in the eCash blockchain. This rule was previously enforced by policy, so no wallet update is required.

Miner fund moved out of consensus rules

The miner fund, part of the block reward that is funding eCash network development, will no longer be enforced by consensus. It will be enforced by policy, and a block that contains an invalid or no miner fund output will be rejected by Avalanche Post-Consensus. This will make it easier for updating the miner fund parameters such as the acceptable addresses.

Removed chained transactions limits

After the upgrade activates, Bitcoin ABC nodes will start accepting an unlimited number of chained transactions in the mempool. This was limited to 50 transactions before the upgrade. Note that this is a policy change and has no impact on the consensus rules.

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How do I upgrade?

The process of upgrading your node is straightforward: simply stop the currently running node, download the new version, and start the new version. Here are some example instructions for upgrading from version 0.26.13 to the latest version (0.27.0) on Linux:

• Shut down the node: ./bitcoin-abc-0.26.13/bin/bitcoin-cli stop
• Download the new version archive from the website: wget https://download.bitcoinabc.org/0.27.0/linux/bitcoin-abc-0.27.0-x86_64-linux-gnu.tar.gz
• Extract the archive: tar xzf bitcoin-abc-0.27.0-x86_64-linux-gnu.tar.gz
• Restart the node with the new version: ./bitcoin-abc-0.27.0/bin/bitcoind -daemon
• Clean up old version and archives (optional):
• rm -rf bitcoin-abc-0.26.13
• rm -f bitcoin-abc-0.26.13-x86_64-linux-gnu.tar.gz
• rm -f bitcoin-abc-0.27.0-x86_64-linux-gnu.tar.gz

Do I need to upgrade my wallet?

The network upgrade only affects full nodes. Other eCash software, including wallets such as Electrum ABC are not affected by the network upgrade.

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More information: https://www.bitcoinabc.org/upgrade/