Technology, Klaytn Core

Klaytn v1.12.1 Release Notice

We are pleased to announce that Klaytn v1.12.1 has been released.

Klaytn v1.12.1 contains bug fixes and Cypress mainnet hardfork block number configuration. The hardforks have already been applied to the Baobab testnet.

IMPORTANT: Klaytn v1.12.1 contains a hardfork upgrade that results in changes that are not backward compatible. All Cypress nodes must be upgraded to v1.12.0 or later before the target block number.

This version includes two distinct hardforks. The first is equivalent to the features of the Ethereum Cancun hardfork, and the second is an optional hardfork implementing Randao on-chain randomness. Refer to the v1.12.0 Release Notice for details.

Here’s the hardfork schedule for the Cypress mainnet:

Cypress mainnet

  • Block number: 147534000 (estimated time: 04 Mar, 10:00 AM UTC+9)
  • Hardfork contents: Cancun hardfork, Randao hardfork


Public EN operators can enable the rpc.gascap configuration to reduce loads from heavy RPC calls. It is recommended to add the –rpc.gascap 300000000 (300mil gas) flag, but you should choose an appropriate value based on your node’s capacity.

The illegal instruction (SIGILL) error that occurred in v1.12.0 was resolved in v1.12.1. Even if some Intel CPU models do not support certain instructions, the linux-amd64 binary will function. On ARM Macs, the darwin-amd64 binary will work.


  • Added the klay_getProof and klay_getProof APIs (#2068)
  • Enhanced information retrieved from the klay_getBlockWithConsensusInfo API and the ‘ken util decode-extra’ command (#2088, #2101)
  • Modified the output values from the default tracer in debug trace APIs,  (#2090)
  • Dynamically enabled optimization instructions depending on CPU type to prevent the illegal instruction (SIGILL) error (#2091)


  • Exposed debug APIs via IPC even if disabled via RPC (#2075)
  • Removed the computation cost cap from the call, estimateGas, and estimateComputationCost APIs (#2086)
  • Fixed the slow node startup issue (#2064, #2074)
  • Fixed the slow node termination and debug_setHead APIissue (#2100)
  • Fixed the block sync problem related to Randao (#2092)
  • Fixed the bug where some APIs ignored the ‘input’ field in transaction parameters (#2085)
  • Fixed the klay_getBlockWithConsensusInfo API bug (#2071)
  • Fixed the debug_chaindbProperty and debug_chaindbCompact APIs and deleted the debug_getDBProperty API (#2062)