Release 3.4.0 Notes

3.4.0

New features

• rollback set head and purge blocks antecedent to specified block number
• --chain-config replaces init genesis, allowing ever finer-grained control over a private network configuration
• dump-chain-config is useful for establishing starting-point customnet.json external chain configurations
• --chain allows you to specify chain to run by "chainID", ie "mainnet", "customnet"...

Data directory migration

We've renamed the base default data directory from "Ethereum" to "EthereumClassic" (or OS-sensible variants). Along with this and the implementation of --chain flag, chain-based data are now store by named subdirectories under the parent data dir. This means

.../Ethereum/testnet/chaindata
.../Ethereum/testnet/nodes
.../Ethereum/testnet/keystore
.../Ethereum/chaindata # mainnet defaults
.../Ethereum/nodes
.../Ethereum/keystore

becomes:

.../EthereumClassic/morden/chaindata
.../EthereumClassic/morden/nodes
.../EthereumClassic/morden/keystore
.../EthereumClassic/mainnet/chaindata # mainnet defaults
.../EthereumClassic/mainnet/nodes
.../EthereumClassic/mainnet/keystore

Geth will attempt to migrate (rename/mv) any relevant data from the old schema to the new, unless:

• it can't find ETC (vs ETH) data in the old directories,
• the "old" data isn't in the default locations,
• or you override the in-use defaults with the --data-dir, --chain, or --external-config flags.