feat: remove fip-0115 feature flag

CHANGELOG.md

@@ -29,12 +29,14 @@
 
 ### Added
 
-- [#6913](https://github.com/ChainSafe/forest/issues/6913): Added support for NV28 for devnets. Use `FOREST_FIREHORSE_HEIGHT` environment variable to set the upgrade height. Note that `FIP-0115` is not yet automatically activated with this change.
+- [#6913](https://github.com/ChainSafe/forest/issues/6913): Added support for NV28 for devnets. Use `FOREST_FIREHORSE_HEIGHT` environment variable to set the upgrade height.
 
 ### Changed
 
 ### Removed
 
+- [#6948](https://github.com/ChainSafe/forest/pull/6948): Removed the `FOREST_FEES_FIP0115HEIGHT` environment variable. The `FIP-0115` will be automatically activated at `FireHorse` network upgrade.
+
 ### Fixed
 
 ## Forest v0.33.0 "Patroclus"

scripts/devnet/.env

@@ -1,4 +1,4 @@
-LOTUS_IMAGE=ghcr.io/chainsafe/lotus-devnet:2026-04-20-4f7bde5
+LOTUS_IMAGE=ghcr.io/chainsafe/lotus-devnet:2026-04-21-adb50d9
 FOREST_DATA_DIR=/forest_data
 LOTUS_DATA_DIR=/lotus_data
 FIL_PROOFS_PARAMETER_CACHE=/var/tmp/filecoin-proof-parameters

scripts/devnet/lotus.dockerfile

@@ -13,7 +13,7 @@ RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --no-modify-path --profile mini
 
 ENV PATH="/root/.cargo/bin:${PATH}"
 
-RUN git clone https://github.com/filecoin-project/lotus.git . && git reset --hard d036ad9521d6621b5393d3d1b707a9994e94feed
+RUN git clone https://github.com/filecoin-project/lotus.git . && git reset --hard 7db670848518732139425d36f8baaad7518e569a
 
 # https://github.com/Filecoin-project/filecoin-ffi?tab=readme-ov-file#building-from-source
 RUN CGO_CFLAGS_ALLOW="-D__BLST_PORTABLE__" \

src/chain/store/base_fee.rs

@@ -1,25 +1,15 @@
 // Copyright 2019-2026 ChainSafe Systems
 // SPDX-License-Identifier: Apache-2.0, MIT
 
-use std::sync::LazyLock;
-
 use crate::blocks::Tipset;
 use crate::message::MessageReadWrite;
 use crate::shim::clock::ChainEpoch;
 use crate::shim::econ::{BLOCK_GAS_LIMIT, TokenAmount};
-use crate::utils::misc::env::env_or_default;
 use ahash::{HashSet, HashSetExt};
 use fvm_ipld_blockstore::Blockstore;
 
 use super::weighted_quick_select::weighted_quick_select;
 
-/// FIP-0115 base fee activation epoch, controlled via `FOREST_FEES_FIP0115HEIGHT`.
-/// Defaults to `-1` (disabled). Setting to a non-negative value activates premium-based
-/// base fee computation at that epoch.
-/// WARNING: This is a consensus-breaking change and should only be used for testing.
-static FIP0115_HEIGHT: LazyLock<ChainEpoch> =
-    LazyLock::new(|| env_or_default("FOREST_FEES_FIP0115HEIGHT", -1));
-
 pub const BLOCK_GAS_TARGET_INDEX: u64 = BLOCK_GAS_LIMIT * 80 / 100 - 1;
 
 /// Used in calculating the base fee change.
@@ -64,17 +54,15 @@ pub fn compute_base_fee<DB>(
     db: &DB,
     ts: &Tipset,
     smoke_height: ChainEpoch,
+    firehorse_height: ChainEpoch,
 ) -> Result<TokenAmount, crate::chain::Error>
 where
     DB: Blockstore,
 {
-    // FIP-0115: https://github.com/filecoin-project/FIPs/blob/master/FIPS/fip-0115.md
-    let fip0115_height = *FIP0115_HEIGHT;
-    if fip0115_height >= 0 && ts.epoch() >= fip0115_height {
-        return compute_next_base_fee_from_premiums(db, ts);
+    if ts.epoch() < firehorse_height {
+        return compute_next_base_fee_from_utlilization(db, ts, smoke_height);
     }
-
-    compute_next_base_fee_from_utlilization(db, ts, smoke_height)
+    compute_next_base_fee_from_premiums(db, ts)
 }
 
 fn compute_next_base_fee_from_premiums<DB>(
@@ -229,7 +217,8 @@ mod tests {
         });
         let ts = Tipset::from(h0);
         let smoke_height = ChainConfig::default().epoch(Height::Smoke);
-        assert!(compute_base_fee(&blockstore, &ts, smoke_height).is_err());
+        let firehorse_height = ChainConfig::default().epoch(Height::FireHorse);
+        assert!(compute_base_fee(&blockstore, &ts, smoke_height, firehorse_height).is_err());
     }
 
     #[test]

src/chain_sync/tipset_syncer.rs

@@ -240,14 +240,20 @@ async fn validate_block<DB: Blockstore + Sync + Send + 'static>(
     // Base fee check
     validations.spawn_blocking({
         let smoke_height = state_manager.chain_config().epoch(Height::Smoke);
+        let firehorse_height = state_manager.chain_config().epoch(Height::FireHorse);
         let base_tipset = base_tipset.shallow_clone();
         let block_store = state_manager.blockstore_owned();
         let block = block.shallow_clone();
         move || {
-            let base_fee = crate::chain::compute_base_fee(&block_store, &base_tipset, smoke_height)
-                .map_err(|e| {
-                    TipsetSyncerError::Validation(format!("Could not compute base fee: {e}"))
-                })?;
+            let base_fee = crate::chain::compute_base_fee(
+                &block_store,
+                &base_tipset,
+                smoke_height,
+                firehorse_height,
+            )
+            .map_err(|e| {
+                TipsetSyncerError::Validation(format!("Could not compute base fee: {e}"))
+            })?;
             let parent_base_fee = &block.header.parent_base_fee;
             if &base_fee != parent_base_fee {
                 return Err(TipsetSyncerError::Validation(format!(

src/message_pool/msgpool/provider.rs

@@ -97,7 +97,8 @@ impl<DB: Blockstore> Provider for ChainStore<DB> {
 
     fn chain_compute_base_fee(&self, ts: &Tipset) -> Result<TokenAmount, Error> {
         let smoke_height = self.chain_config().epoch(Height::Smoke);
-        crate::chain::compute_base_fee(self.blockstore(), ts, smoke_height)
+        let firehorse_height = self.chain_config().epoch(Height::FireHorse);
+        crate::chain::compute_base_fee(self.blockstore(), ts, smoke_height, firehorse_height)
             .map_err(|err| err.into())
     }
 

src/rpc/methods/miner.rs

@@ -133,15 +133,18 @@ impl RpcMethod<1> for MinerCreateBlock {
             .get_miner_work_addr(*lookback_state, &block_template.miner)?;
 
         let parent_weight = weight(store, &parent_tipset)?;
-        //let parent_weight = parent_tipset.weight().to_owned();
+        let heights = &ctx.chain_config().height_infos;
         let parent_base_fee = compute_base_fee(
             store,
             &parent_tipset,
-            ctx.chain_config()
-                .height_infos
+            heights
                 .get(&Height::Smoke)
                 .context("Missing Smoke height")?
                 .epoch,
+            heights
+                .get(&Height::FireHorse)
+                .context("Missing FireHorse height")?
+                .epoch,
         )?;
         let ExecutedTipset {
             state_root,