The Polygon proof-of-stake (PoS) network is set to launch the Heimdall v2 consensus layer upgrade on July 10 – the “most technically complex hard fork” since the network’s inception in 2020, according to Polygon CEO Sandeep Nailwal.

Heimdall v2 is a modernized and revamped consensus client that remains central to Polygon PoS operations. It manages validators, block producer selection, state synchronization between Ethereum and Polygon, and other core functions.

It introduces CometBFT for consensus, replacing Tendermint, which streamlines transaction processing and improves state synchronization.

This story is an excerpt from the Unchained Daily newsletter.

It will also result in a dramatic reduction in transaction finality, from around 90 seconds to just 5 seconds, enabling much faster network confirmations.

The fork will be executed tomorrow, July 10, 2025.

Nailwal warned that the hard fork could see finality lag by around 3 hours during the migration phase, and that while unlikely, a “large reorg” was still possible.