0xPolygon/bor v2.5.6 | Chain Release Info

This is a mandatory release for Bor that introduces the Dandeli hard fork on the mainnet.

All node operators must upgrade to this version.

Dandeli Hard Fork Details:
The hard fork is scheduled for block number 81,424,000, which is estimated to be mined on January 9th, 2026, around 2:00 PM UTC.

The primary goal of the Dandeli HF is to mitigate gas price spikes and increase effective network throughput. It achieves this by modifying the EIP-1559 gas target calculation. The block gas target will be increased from 50% to 66% of the total block gas limit, making the base fee increase more slowly during surges in network activity.

Other Key Improvements and Fixes:

Miner Stability Fixes:
- A fix has been implemented to prevent a node from stalling by correctly deleting a pending task after a block is successfully sealed. (PR #1929)
- A race condition that could cause duplicate block sealing work has been resolved by tracking pending work using the block number. (PR #1943)

Performance and Consensus Improvements:
- The "recommit" mechanism has been removed to prevent wasting resources on reprocessing a block, freeing up resources for the next block. This change also fixes how the parent block's timestamp is tracked, preventing incorrect time progression. (PR #1938)
- A bug in the parallel EVM has been fixed to ensure selfdestruct operations are correctly reverted when a transaction fails. (PR #1918)

P2P Layer Enhancement:
- Functionality has been added to temporarily ban misbehaving peers at the P2P layer, improving network health and stability. (PR #1922)

Critical Bug Fixes:
- A missing chain validator service setup has been fixed. This was preventing the node from correctly detecting and rejecting invalid headers. (PR #1957)
- RPC APIs have been improved, with fixes to the traceBlock API and correct handling of maxFeePerGas for StateSync transaction types. (PR #1959, #1952)

Bor v2.5.6 is an important release containing **Dandeli hard fork on mainnet Network**. The HF is scheduled on block number [81424000](https://polygonscan.com/block/countdown/81424000) which is estimated to be mined at **9th Jan 2026, 2 PM UTC**. It adjusts the gas target calculations to mitigate gas price spikes and to increase effective network throughput.

## What's Changed
* backport by @marcello33 in https://github.com/0xPolygon/bor/pull/1919
* Fix parallel evm revert by @avalkov in https://github.com/0xPolygon/bor/pull/1918
* p2p: added functionality to temporarily ban peers to prevent connections by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1922
* chore: bump kurtosis-pos by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1923
* backport v2.5.4 by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1926
* fix(miner): delete pending task after successful block sealing to prevent node stall by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1929
* v2.5.5 release by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1936
* chore: backport master to develop by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1937
* Remove Recommit and Fix Parent Actual Time track on Prepare by @lucca30 in https://github.com/0xPolygon/bor/pull/1938
* chore: update deps by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1939
* V2.5.6 candidate by @lucca30 in https://github.com/0xPolygon/bor/pull/1941
* Backport master to develop by @lucca30 in https://github.com/0xPolygon/bor/pull/1942
* Revert "V2.5.6 candidate" by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1947
* Revert "Backport master to develop" by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1948
* fix: ignore invalid signer error for specific block range by @avalkov in https://github.com/0xPolygon/bor/pull/1944
* fix(miner): track pending work using block number to avoid duplicate block building work by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1943
* fix(rpc): maxFeePerGas and maxPriorityFeePerGas for StateSyncTx type by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1952
* chore: bump kurtosis-pos by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1954
* Fix missing chain validator service setup by @Raneet10 in https://github.com/0xPolygon/bor/pull/1957
* fix(api): traceBlock by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/1959
* Dandeli HF: modify block gas target calculations by @manav2401 in https://github.com/0xPolygon/bor/pull/1968
* v2.5.6 stable release by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1949


**Full Changelog**: https://github.com/0xPolygon/bor/compare/v2.5.5...v2.5.6

Chain Releases

0xPolygon/bor - v2.5.6

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