This Month in Forest — September 2025

[AlexeyKrasnoperov]

This Month in Forest — September 2025 🌲

Welcome to the September edition of This Month in Forest! We are excited to share the latest updates and improvements to the Forest Filecoin client (and more!).

Highlights

• This month, we shipped two major releases:
  • v0.30.0 "Eärendil" – a mandatory release for Calibration network node operators. Activates the NV27 Golden Week upgrade at epoch 3_007_294 (Wed 10 Sep 23:00:00 UTC 2025).
  • v0.30.1 "Laurelin" – a mandatory release for Mainnet node operators. Activates the NV27 Golden Week upgrade at epoch 5_348_280 (Wed 24 Sep 23:00:00 UTC 2025).
  • Both releases also bring improvements for snapshot generation and inspection, along with minor fixes and cleanup.
  • Forest NV47 Support Announcement: #6053
• We increased the calibnet USDFC drip due to increased demand. (feat: increase calibnet global drip to 200x forest-explorer#311)
• Our Snapshots pages got a new look, and we now provide four kinds of snapshots:

• A major milestone for F3: the new light client functionality has been merged into rust-f3, developed by the IPC team. Thanks @moshababo 🏆 (Add F3 light client functionality rust-f3#27)
• Forest snapshot service is transitioning to v2 snapshots containing F3 data. (#6115)
  • Calibnet: v2 live since Sept 24.
  • Mainnet: v2 serving starts Oct 9.

Development

Network Upgrade Preparations

September was all about getting Forest ready for the NV27 Golden Week upgrade. We updated the FVM to v4.7.3 and laid down the skeleton and base migration for NV27. The v17 actors bundle was integrated together with ~2k network tests against Lotus to ensure compatibility.

NV27 activation was then wired across networks: Butterflynet, Calibnet, and finally Mainnet, where the upgrade epoch was locked at 5_348_280. To help operators track the rollout, we also added Prometheus metrics exposing network_version and actor_version.

With these steps in place, Forest is aligned with the upcoming upgrade and ready for a smooth transition on mainnet.

StateDecodeParams

This month, we completed the remaining functionality of the StateDecodeParams method, and it's now fully supported in Forest. This method is key for turning low-level chain data into something readable and meaningful, which helps developers, explorers, and node operators better understand what's happening on-chain.
While implementing the functionality, the team uncovered several issues in the reference Go code, including missing methods (1, 2, 3) and RPC method bugs.

Tooling Improvements

We shipped several tooling enhancements this month to make Forest more powerful and convenient to use:

• forest-cli f3 ready now supports a --no-progress-timeout option, allowing the command to exit when F3’s head makes no progress within a given timeout. (#6057)
• forest-tool api serve gains a --index-backfill-epochs flag, letting users control how many epochs of backfill to run for the index subsystem. (#6068)
• New command forest-cli state actor-cids added, which helps query actor CIDs in the chain state. (#6061)
• forest-cli snapshot export-diff was introduced, enabling differential snapshot exports (changes between snapshots). (#6074)
• Exporting “spine-only” snapshots is now supported using forest-cli snapshot export -d 0, producing a lighter snapshot with just the spine. (#6097)

Other

As always, see the CHANGELOG for details. Note that it contains primarily client-facing changes, so if you're interested in the nitty-gritty details, you'll need to go through the commit history. 🤓