Conflux v2.1.0-testnet

This release introduces a new hardfork. All nodes should be upgraded before the epoch number reaches 88100000.

Incompatible Changes

• CIP-94 (https://github.com/Conflux-Chain/CIPs/blob/master/CIPs/cip-94.md): This CIP proposes to use on-chain DAO voting to decide and update reward parameters without hardfork.
• CIP-97 (https://github.com/Conflux-Chain/CIPs/blob/master/CIPs/cip-97.md): This CIP proposes to remove account’s staking lists.
• CIP-98 (https://github.com/Conflux-Chain/CIPs/blob/master/CIPs/cip-98.md): Fix a bug in BLOCKHASH opcode in eSpace.
• CIP-99 (https://github.com/Conflux-Chain/CIPs/blob/master/CIPs/cip-99.md): Allow more not-voting terms before we force-retire a node, and make the unlock period of a retiring node shorter to allow the node to rejoin the PoS voting faster.

Configuration Improvement

• Add configuration enable_single_mpt_storage to enable storing all history states. Set single_mpt_space = "evm" to only store eSpace states. Note that you'll need to resync an archive node to reconstruct all the history states.

Storage Improvement

• Allow snapshots to be removed during recovery. This reduces the disk space requirement for full node sync or recovery.

RPC Improvement

• Support eth_subscribe and eth_unsubscribe in eSpace RPCs.
• Add a RPC method cfx_getParamsFromVote to return the currently used value of the voted parameters.
• Return null for getting skipped transactions and receipts. Whether they will be returned was nondeterministic before, but now they are ensured to be null.