Consensus Break on Polygon PoS Network Triggers Mandatory Client Upgrade
The Polygon ecosystem faced an unexpected disruption. Polygon Labs has issued an urgent notification confirming that a significant number of Polygon PoS nodes, still operating on outdated client software, have fallen out of consensus with the mainnet following the activation of the Austin and Kyoto hard forks. This renders these nodes unable to validate transactions or participate in network operations, requiring immediate action.
Hard Forks Set Upgrade Deadlines, Version Requirements Specified
The situation was directly triggered by two scheduled network upgrades. The Austin hard fork activated at mainnet block height 91,949,700. Polygon Labs explicitly states that after this point, all PoS nodes must upgrade their Bor client to version v2.10.0 or higher to maintain consensus.
Concurrently, the Kyoto hard fork activated at block height 51,533,000. For this upgrade, nodes must run Heimdall client version v0.11.0 or above. Any node failing to meet either requirement is currently offline or invalid.
Beyond an Upgrade: Critical Security Patches Applied
Behind this mandatory upgrade lies crucial reinforcement for network stability and security. The Austin fork specifically addressed two vulnerabilities in the Bor client that posed serious risks.
- Gas Accounting Flaw: Previously, the gas consumed by state sync events from the Ethereum mainnet to Polygon was not counted against the gas limit. This defect could lead to sustained resource drain, ultimately slowing down new block processing and impacting overall network throughput.
- Memory Risk Vulnerability: The transaction dependency (TxDependency) field lacked a proper size limit. A malicious actor could potentially craft transactions sending oversized data packets to peer nodes, causing them to run out of memory and crash, creating an attack vector.
Therefore, this upgrade is not merely about restoring node functionality; it is a critical security patch that must be applied by all network participants.
What Should Node Operators Do Next?
For affected node operators, the immediate priority is to check the current versions of their Bor and Heimdall clients and upgrade to the specified or later versions as per official guidance. After upgrading, nodes must re-synchronize to catch up with the latest network state before they can re-join consensus and resume normal operations. Delaying the upgrade will likely result in prolonged service interruption and failure to stay current with the network.