0xPolygon/bor - v2.6.0 New

Published: Feb 18, 2026

MAINNET Deadline: Mar 4, 2026

Release Summary

The Bor v2.6.0 release is now available. This is a mandatory update that prepares for the upcoming Lisovo/LisovoPro hardfork and includes significant performance and stability improvements.

Lisovo Hardfork Announcement
This release defines the Lisovo hardfork, scheduled for mainnet at block 83756500, estimated to occur around 2 PM UTC on March 4th, 2026. The hardfork will introduce the following changes:

CLZ Opcode Support: Adds the "Count Leading Zeros" opcode.
P256 Gas Cost Updates: Adjusts gas costs for the P256 precompile.

Key Features and Performance Improvements

Peer Consensus-Based Witness Verification: To combat incorrect witness data from peers, nodes will now query other random peers to verify witness sizes before downloading. This adds a layer of security and prevents unnecessary bandwidth usage.

Transaction Rebroadcast Mechanism: A new mechanismperiodically rebroadcasts transactions that may have become stuck in the txpool, improving their chances of being included in a block.

Dynamic EIP-1559 Parameters: Block producers now have more flexibility in adjusting EIP-1559 parameters, allowing for more dynamic responses to network conditions.

Improved Pruner Reorg Handling: The pruner is now more robust against chain reorgs (both online and offline), correctly handling reverted data and ensuring consistency.

Late Block Build Time Fix: An issue causing the production of empty blocks when a preceding block was delayed has been fixed. This ensures new blocks always have sufficient time to be filled with transactions.

Witness Memory Cache: A new LRU memory cache for witnesses has been added to reduce database reads and improve performance.

PIP-82 Implementation: Changes related to the "Agentic Commerce Gas Program" have been implemented in the `BurntContract`.

Critical Stability Fixes

Memory and Goroutine Leak Fixes: This release patches a goroutine leak that occurred when Heimdall was unreachable and caps the number of headers read during verification to prevent Out-Of-Memory (OOM) errors.

Clean Shutdowns: An issue where in-flight queries to Heimdall could block the shutdown process has been resolved, preventing unclean shutdowns and potential state corruption on restart.

Concurrency Fixes: Several race conditions and a panic related to concurrent map writes in the witness protocol have been fixed, enhancing overall node stability.

RPC Crash Fix: A crash in the `eth_simulateV1` RPC method handler has been resolved.

Upstream Updates
This version of Bor incorporates updates from `go-ethereum` up to version v1.16.8, including its security patches and improvements.

Release Notes

## Description

Bor `v2.6.0` release defines the upcoming Lisovo/LisovoPro hardfork, includes performance improvements, and upstream updates from `go-ethereum`.                                               
   
The Mainnet Testnet Lisovo Hardfork will happen on block `[83756500](https://polygonscan.com/block/countdown/83756500)`, at around 2 PM UTC, March 4th, 2026.
The changes included in this HF are:
- `CLZ` Opcode Support
- `P256` Gas Cost Updates

With regards to upstream updates, we are rolling out changes up to `go-ethereum v1.16.8`

Other major changes include:
- Security fixes
- Go bump
- Bugs fixes
- Implementation of [PIP-82](https://forum.polygon.technology/t/pip-82-agentic-commerce-gas-program/21721) (changes in `BurntContract`)
- Peer Consensus-Based Witness Verification (#1766)
- Dynamic EIP-1559 Parameters (#1989)
- Transaction Rebroadcast Mechanism (#1992, #2028, #2037)
- Validator Set Overrides (#1958)
- Witness Memory Cache (#1962)
- Block Production Metrics (#1991)
- Late Block Build Time (#1963)
- Pruner Reorg Handling (#1916)
- Race Condition Fixes (#1946) 
- Witness Protocol Concurrency Fix (#2023)

Also, the release includes minor bug fixes (crash in `eth_simulateV1`, stateless mode stability, `state-sync` support for tracer, ...), more tests and improvements around code quality.

## What's Changed
* eth/protocols/wit: made protocol version consistent by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1940
* chore: fix function name in comment and correct spelling error in config.go by @findfluctuate in https://github.com/0xPolygon/bor/pull/1956
* chore: remove repetitive word in comment by @liuyueyangxmu in https://github.com/0xPolygon/bor/pull/1909
* core/txpool: added nil checks to prevent crash in stateless mode by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1961
* Enforce patch code coverage by @cffls in https://github.com/0xPolygon/bor/pull/1964
* backport v2.5.6 into develop by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1971
* core, eth: added LRU memory cache to save witnesses in memory by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1962
* consensus/bor: ensure late blocks have sufficient build time by @cffls in https://github.com/0xPolygon/bor/pull/1963
* backport v2.5.7 by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1985
* Return nil from heimdall mock on milestone/checkpoint by @cffls in https://github.com/0xPolygon/bor/pull/1988
* fix randomly failing TestCalcBaseFeeDelhi by @cffls in https://github.com/0xPolygon/bor/pull/1987
* Increase veblop timeout to 8 seconds by @cffls in https://github.com/0xPolygon/bor/pull/1986
* fix(rpc): eth_simulateV1 method handler crash by @ChanHongMing in https://github.com/0xPolygon/bor/pull/1955
* BP Metrics by @lucca30 in https://github.com/0xPolygon/bor/pull/1991
* txpool: add stuck transaction rebroadcast mechanism by @cffls in https://github.com/0xPolygon/bor/pull/1992
* fix: add bor hfs to description and readheadertimeout in config by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2003
* init: CLAUDE.md file by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2000
* consensus/eip1559: add missing bhilai HF tests by @manav2401 in https://github.com/0xPolygon/bor/pull/1990
* Validator Set Overrides on Config by @lucca30 in https://github.com/0xPolygon/bor/pull/1958
* Add Claude Assistant Workflows by @adamdossa in https://github.com/0xPolygon/bor/pull/2006
* bind, params: fix bind/v2 tests and warn about invalid config/flag by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2007
* Switch to GCR for our CI / CD instead of Docker Hub by @adamdossa in https://github.com/0xPolygon/bor/pull/2011
* fix(ci): use custom kurtosis branch by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2012
* eth: implemented peer consensus based witness verification by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/1766
* Various improvements  by @marcello33 in https://github.com/0xPolygon/bor/pull/1950
* ci: load kurtosis images from gcr instead of docker hub by @leovct in https://github.com/0xPolygon/bor/pull/2014
* Dynamic EIP-1559 params setup by @lucca30 in https://github.com/0xPolygon/bor/pull/1989
* Test validator's ability to rewind upon span rotation by @cffls in https://github.com/0xPolygon/bor/pull/1960
* geth upstream v1.16.7 by @Raneet10 in https://github.com/0xPolygon/bor/pull/1974
* eth/tracers: include state sync tx in traces post-Madhugiri by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2010
* eth: fix concurrent map writes panic in witness protocol by @cffls in https://github.com/0xPolygon/bor/pull/2023
* backport v2.5.8 by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/2025
* upstream v1.16.8 by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/2024
* fix(api): tracers tests for state-sync tx by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2026
* Updating enodes for mainnet and amoy by @sanketsaagar in https://github.com/0xPolygon/bor/pull/2021
* pruner: covering reorg scenarios by @lucca30 in https://github.com/0xPolygon/bor/pull/1916
* geth upstream v1.16.4 by @marcello33 in https://github.com/0xPolygon/bor/pull/1839
* Enable rebroadcast by default by @cffls in https://github.com/0xPolygon/bor/pull/2028
* Fix race conditions detected in make test-race by @cffls in https://github.com/0xPolygon/bor/pull/2027
* revert: P256VerifyGas to 3450 by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2030
* fix(ci): test-state-sync by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2032
* Enable rebroadcast by default by @cffls in https://github.com/0xPolygon/bor/pull/2037
* Install polycli in kurtosis e2e by @cffls in https://github.com/0xPolygon/bor/pull/2036
* lisovo: CLZ opcode and P256 gas cost changes by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2040
* consensus/misc/eip4844: small update to fix simulatev1 crash by @pratikspatil024 in https://github.com/0xPolygon/bor/pull/2054
* core, internal, params: lisovoPro HF and version bump by @marcello33 in https://github.com/0xPolygon/bor/pull/2055
* consensus/bor: fix goroutine leak in runMilestoneFetcher when Heimdall is unreachable by @cffls in https://github.com/0xPolygon/bor/pull/2056
* fix(shutdown): cancel in-flight Heimdall queries on engine shutdown by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2058
* consensus/bor: fix sub-second late block detection producing empty blocks by @cffls in https://github.com/0xPolygon/bor/pull/2060
* fix(core): cap verifyPendingHeaders to prevent OOM from unbounded header reads by @kamuikatsurgi in https://github.com/0xPolygon/bor/pull/2057
* builder, internal, params: pip-82 and lisovo HF in mainnet by @marcello33 in https://github.com/0xPolygon/bor/pull/2064
* v2.6.0 by @marcello33 in https://github.com/0xPolygon/bor/pull/2065

## New Contributors
* @findfluctuate made their first contribution in https://github.com/0xPolygon/bor/pull/1956
* @liuyueyangxmu made their first contribution in https://github.com/0xPolygon/bor/pull/1909
* @ChanHongMing made their first contribution in https://github.com/0xPolygon/bor/pull/1955

**Full Changelog**: https://github.com/0xPolygon/bor/compare/v2.5.9...v2.6.0

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