Polygon deploys Heimdall 2.0 hard fork cutting finality to 4 seconds

9-7-2025 – Polygon executed its most technically complex hard fork since launching in 2020, upgrading its proof-of-stake blockchain with the new Heimdall 2. 0 consensus layer as the native POL token surged nearly 10% to month-highs around $0. 20. The upgrade replaces legacy Tendermint infrastructure from 2018-2019 with modern CometBFT architecture, dramatically improving network performance metrics source: https://www.cointrackdaily.com/polygon-deploys-heimdall-2-0-hard-fork-cutting-finality-to-4-seconds/