diff --git a/contracts/0.4.24/oracle/LegacyOracle.sol b/contracts/0.4.24/oracle/LegacyOracle.sol
index f894df5c03..06b148ddcf 100644
--- a/contracts/0.4.24/oracle/LegacyOracle.sol
+++ b/contracts/0.4.24/oracle/LegacyOracle.sol
@@ -25,7 +25,8 @@ interface IHashConsensus {
 
     function getFrameConfig() external view returns (
         uint256 initialEpoch,
-        uint256 epochsPerFrame
+        uint256 epochsPerFrame,
+        uint256 fastLaneLengthSlots
     );
 
     function getCurrentFrame() external view returns (
@@ -147,7 +148,7 @@ contract LegacyOracle is Versioned, AragonApp {
             uint64 genesisTime
         )
     {
-        (, uint256 epochsPerFrame_) = _getAccountingConsensusContract().getFrameConfig();
+        (, uint256 epochsPerFrame_,) = _getAccountingConsensusContract().getFrameConfig();
         epochsPerFrame = uint64(epochsPerFrame_);
 
         ChainSpec memory spec = _getChainSpec();
@@ -365,7 +366,7 @@ contract LegacyOracle is Versioned, AragonApp {
     {
         IHashConsensus consensus = IHashConsensus(_accountingOracleConsensusContract);
         (uint256 slotsPerEpoch, uint256 secondsPerSlot, uint256 genesisTime) = consensus.getChainConfig();
-        (, uint256 epochsPerFrame_) = consensus.getFrameConfig();
+        (, uint256 epochsPerFrame_,) = consensus.getFrameConfig();
 
         spec.epochsPerFrame = uint64(epochsPerFrame_);
         spec.slotsPerEpoch = uint64(slotsPerEpoch);
diff --git a/contracts/0.8.9/oracle/AccountingOracle.sol b/contracts/0.8.9/oracle/AccountingOracle.sol
index 14dce0d59d..9776aacd0a 100644
--- a/contracts/0.8.9/oracle/AccountingOracle.sol
+++ b/contracts/0.8.9/oracle/AccountingOracle.sol
@@ -495,7 +495,7 @@ contract AccountingOracle is BaseOracle {
         internal view returns (uint256)
     {
         (uint256 initialEpoch,
-            uint256 epochsPerFrame) = IConsensusContract(consensusContract).getFrameConfig();
+            uint256 epochsPerFrame,) = IConsensusContract(consensusContract).getFrameConfig();
 
         (uint256 slotsPerEpoch,
             uint256 secondsPerSlot,
diff --git a/contracts/0.8.9/oracle/BaseOracle.sol b/contracts/0.8.9/oracle/BaseOracle.sol
index 255c1fec5a..f3e5a7cb5e 100644
--- a/contracts/0.8.9/oracle/BaseOracle.sol
+++ b/contracts/0.8.9/oracle/BaseOracle.sol
@@ -25,7 +25,11 @@ interface IConsensusContract {
         uint256 genesisTime
     );
 
-    function getFrameConfig() external view returns (uint256 initialEpoch, uint256 epochsPerFrame);
+    function getFrameConfig() external view returns (
+        uint256 initialEpoch,
+        uint256 epochsPerFrame,
+        uint256 fastLaneLengthSlots
+    );
 
     function getInitialRefSlot() external view returns (uint256);
 }
diff --git a/test/0.4.24/contracts/HashConsensus__MockForLegacyOracle.sol b/test/0.4.24/contracts/HashConsensus__MockForLegacyOracle.sol
index b0bc31c089..89623ecba7 100644
--- a/test/0.4.24/contracts/HashConsensus__MockForLegacyOracle.sol
+++ b/test/0.4.24/contracts/HashConsensus__MockForLegacyOracle.sol
@@ -80,10 +80,11 @@ contract HashConsensus__MockForLegacyOracle is IHashConsensus {
 
     function getFrameConfig() external view returns (
         uint256 initialEpoch,
-        uint256 epochsPerFrame
+        uint256 epochsPerFrame,
+        uint256 fastLaneLengthSlots
     ) {
         FrameConfig memory config = _frameConfig;
-        return (config.initialEpoch, config.epochsPerFrame);
+        return (config.initialEpoch, config.epochsPerFrame, config.fastLaneLengthSlots);
     }
 
     function getCurrentFrame() external view returns (
diff --git a/test/0.8.9/contracts/MockConsensusContract.sol b/test/0.8.9/contracts/MockConsensusContract.sol
index 67dc1971b1..8bcd5fae72 100644
--- a/test/0.8.9/contracts/MockConsensusContract.sol
+++ b/test/0.8.9/contracts/MockConsensusContract.sol
@@ -104,9 +104,9 @@ contract MockConsensusContract is IConsensusContract {
     function getFrameConfig()
         external
         view
-        returns (uint256 initialEpoch, uint256 epochsPerFrame)
+        returns (uint256 initialEpoch, uint256 epochsPerFrame, uint256 fastLaneLengthSlots)
     {
-        return (_frameConfig.initialEpoch, _frameConfig.epochsPerFrame);
+        return (_frameConfig.initialEpoch, _frameConfig.epochsPerFrame, _frameConfig.fastLaneLengthSlots);
     }
 
     function getInitialRefSlot() external view returns (uint256) {