Filecoin's mandatory Lotus 1.37 sets the Solstice upgrade for 19 October and retires Fil+

Serguey Asael Shinder07 October 2026, 07:331 min read

Lotus v1.37.0, published on 6 October, is a mandatory release for Filecoin: it delivers network version 29, codenamed Solstice, and sets the mainnet upgrade for epoch 6470279, 19 October 2026 at 12:59:30 UTC. All Lotus node and storage provider operators on mainnet must upgrade before that epoch.

What Solstice changes. It implements FIP-0118, "Deprecate Fil+ and Fund Services via Block-Reward Split", with built-in actors v19.0.1. According to the release notes:

• every new sector receives maximum quality-adjusted power regardless of its content;
• the verified registry and DataCap actors are frozen;
• the migration installs bootstrap state for the reward actor, resolving the service-weight authority, the service-rewards actor and an initial orchestrator to ID addresses at the upgrade epoch.

What breaks for operators from nv29.

• DataCap and verified-registry writes are refused; the lotus filplus datacap commands retire.
• lotus-miner sectors extend --drop-claims is rejected, and --only-cc is removed in favour of --exclude. Legacy sectors are raised with lotus-miner sectors upgrade-quality.
• StateMinerInitialPledgeCollateral returns an error; use StateMinerInitialPledgeForSector, passing the full sector size as the verified size.
• PreCommitSectorBatch2 rejects non-empty deal_ids.
• F3 Prometheus metric names may gain _seconds or _bytes suffixes after an exporter upgrade; dashboards and alerts on f3_* metrics should be checked. Core lotus_* metrics are unchanged.

The notes also announce one pre-migration scheduled ahead of the upgrade.