diff --git a/replay/replayer.go b/replay/replayer.go
index 12a7e45..49716e8 100644
--- a/replay/replayer.go
+++ b/replay/replayer.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/ecdsa"
+	"encoding/hex"
 	"fmt"
 	"time"
 
@@ -27,6 +28,9 @@ func Follow(
 	targetBlobstreamContractAddress string,
 	targetChainGatewayAddress string,
 	privateKey *ecdsa.PrivateKey,
+	headerRangeFunctionID [32]byte,
+	nextHeaderFunctionID [32]byte,
+	filterRange int64,
 ) error {
 	logger.Info("listening for new proofs on the source chain")
 	sourceBlobstreamX, err := blobstreamxwrapper.NewBlobstreamX(ethcmn.HexToAddress(sourceBlobstreamContractAddress), sourceEVMClient)
@@ -69,10 +73,33 @@ func Follow(
 				continue
 			} else if event.StartBlock > latestTargetContractBlock {
 				logger.Info("the target contract needs to catchup", "event_start_block", event.StartBlock, "target_contract_latest_block", latestTargetContractBlock)
-				err = Catchup(ctx, logger, verify, trpc, sourceEVMClient, targetEVMClient, sourceBlobstreamContractAddress, targetBlobstreamContractAddress, targetChainGatewayAddress, privateKey)
+				err = Catchup(
+					ctx,
+					logger,
+					verify,
+					trpc,
+					sourceEVMClient,
+					targetEVMClient,
+					sourceBlobstreamContractAddress,
+					targetBlobstreamContractAddress,
+					targetChainGatewayAddress,
+					privateKey,
+					headerRangeFunctionID,
+					nextHeaderFunctionID,
+					filterRange,
+				)
 				if err != nil {
 					return err
 				}
+				latestTargetContractBlock, err = targetBlobstreamX.LatestBlock(&bind.CallOpts{Context: ctx})
+				if err != nil {
+					return err
+				}
+				if event.EndBlock == latestTargetContractBlock {
+					// the contract is already up to date
+					logger.Info("contract up to date", "target_contract_latest_block", event.EndBlock)
+					continue
+				}
 			}
 			logger.Debug("getting transaction containing the proof", "nonce", event.ProofNonce.Int64(), "hash", event.Raw.TxHash.Hex(), "start_block", event.StartBlock)
 			tx, _, err := sourceEVMClient.TransactionByHash(ctx, event.Raw.TxHash)
@@ -82,7 +109,8 @@ func Follow(
 
 			logger.Debug("decoding the proof")
 			rawMap := make(map[string]interface{})
-			err = abi.UnpackIntoMap(rawMap, "fulfillCall", tx.Data()[4:])
+			inputArgs := abi.Methods["fulfillCall"].Inputs
+			err = inputArgs.UnpackIntoMap(rawMap, tx.Data()[4:])
 			if err != nil {
 				return err
 			}
@@ -94,6 +122,13 @@ func Follow(
 
 			// update the address to be the target blobstreamX contract for the callback
 			decodedArgs.CallbackAddress = ethcmn.HexToAddress(targetBlobstreamContractAddress)
+			if event.EndBlock-event.StartBlock > 1 {
+				// this is a header range proof
+				decodedArgs.FunctionID = headerRangeFunctionID
+			} else {
+				// this is a next header proof
+				decodedArgs.FunctionID = nextHeaderFunctionID
+			}
 
 			logger.Info("replaying the proof", "nonce", event.ProofNonce.Int64())
 			opts, err := newTransactOptsBuilder(privateKey)(ctx, targetEVMClient, 25000000)
@@ -130,9 +165,10 @@ func Catchup(
 	targetBlobstreamContractAddress string,
 	targetChainGatewayAddress string,
 	privateKey *ecdsa.PrivateKey,
+	headerRangeFunctionID [32]byte,
+	nextHeaderFunctionID [32]byte,
+	filterRange int64,
 ) error {
-	filterRange := int64(5000)
-
 	lookupStartHeight, err := sourceEVMClient.BlockNumber(ctx)
 	if err != nil {
 		return err
@@ -165,7 +201,6 @@ func Catchup(
 		return err
 	}
 
-	// TODO: this could be improved in the future to only get the events needed
 	dataCommitmentEvents, err := getAllDataCommitmentStoredEvents(
 		ctx,
 		logger,
@@ -173,6 +208,7 @@ func Catchup(
 		int64(lookupStartHeight),
 		filterRange,
 		latestSourceContractNonce.Int64(),
+		int64(latestTargetContractBlock),
 	)
 	if err != nil {
 		return err
@@ -202,7 +238,19 @@ func Catchup(
 			if bytes.Equal(coreDataCommitment.DataCommitment.Bytes(), event.DataCommitment[:]) {
 				logger.Info("data commitment verified")
 			} else {
-				logger.Error("data commitment mismatch!! quitting", "proof_nonce_in_source_contract", event.ProofNonce, "start_block", event.StartBlock, "end_block", event.EndBlock)
+				logger.Error(
+					"data commitment mismatch!! quitting",
+					"proof_nonce_in_source_contract",
+					event.ProofNonce,
+					"start_block",
+					event.StartBlock,
+					"end_block",
+					event.EndBlock,
+					"expected_data_commitment",
+					hex.EncodeToString(coreDataCommitment.DataCommitment.Bytes()),
+					"actual_data_commitment",
+					hex.EncodeToString(event.DataCommitment[:]),
+				)
 				return fmt.Errorf("data commitment mistmatch. start height %d end height %d", event.StartBlock, event.EndBlock)
 			}
 		}
@@ -243,6 +291,14 @@ func Catchup(
 		// update the address to be the target blobstreamX contract for the callback
 		decodedArgs.CallbackAddress = ethcmn.HexToAddress(targetBlobstreamContractAddress)
 
+		if event.EndBlock-event.StartBlock > 1 {
+			// this is a header range proof
+			decodedArgs.FunctionID = headerRangeFunctionID
+		} else {
+			// this is a next header proof
+			decodedArgs.FunctionID = nextHeaderFunctionID
+		}
+
 		logger.Info("replaying the proof", "startHeight", startHeight)
 		opts, err := newTransactOptsBuilder(privateKey)(ctx, targetEVMClient, 25000000)
 		if err != nil {
@@ -262,7 +318,17 @@ func Catchup(
 		if err != nil {
 			return err
 		}
-		startHeight = event.EndBlock
+		// make sure the contract was updated
+		latestTargetContractBlock, err = targetBlobstreamX.LatestBlock(&bind.CallOpts{Context: ctx})
+		if err != nil {
+			return err
+		}
+		if latestTargetContractBlock == event.EndBlock {
+			// contract updated successfully, we can advance
+			startHeight = event.EndBlock
+		} else {
+			logger.Error("contract did not update successfully, retrying the same proof", "expected_target_height", event.EndBlock, "actual_target_height", latestTargetContractBlock)
+		}
 	}
 
 	latestTargetContractBlock, err = targetBlobstreamX.LatestBlock(&bind.CallOpts{Context: ctx})
@@ -270,7 +336,7 @@ func Catchup(
 		return err
 	}
 
-	logger.Info("contract up to date", "latest_nonce", latestTargetContractBlock)
+	logger.Info("contract up to date", "latest_target_contract_block", latestTargetContractBlock)
 	return nil
 }
 
@@ -281,6 +347,7 @@ func getAllDataCommitmentStoredEvents(
 	lookupStartHeight int64,
 	filterRange int64,
 	latestSourceContractNonce int64,
+	latestTargetContractBlock int64,
 ) (map[int64]blobstreamxwrapper.BlobstreamXDataCommitmentStored, error) {
 	logger.Info("querying all the data commitment stored events in the source contract...")
 	dataCommitmentEvents := make(map[int64]blobstreamxwrapper.BlobstreamXDataCommitmentStored)
@@ -302,6 +369,7 @@ func getAllDataCommitmentStoredEvents(
 			return nil, err
 		}
 
+		gatheredTheNecessaryEvents := false
 		for {
 			if events.Event != nil {
 				_, exists := dataCommitmentEvents[int64(events.Event.StartBlock)]
@@ -309,6 +377,9 @@ func getAllDataCommitmentStoredEvents(
 					continue
 				} else {
 					dataCommitmentEvents[int64(events.Event.StartBlock)] = *events.Event
+					if int64(events.Event.StartBlock) < latestTargetContractBlock {
+						gatheredTheNecessaryEvents = true
+					}
 				}
 			}
 			if !events.Next() {
@@ -320,6 +391,10 @@ func getAllDataCommitmentStoredEvents(
 			logger.Info("found all events", "count", len(dataCommitmentEvents))
 			break
 		}
+		if gatheredTheNecessaryEvents {
+			logger.Info("found enough events to cover the needed range", "count", len(dataCommitmentEvents))
+			break
+		}
 		logger.Info("found events", "count", len(dataCommitmentEvents))
 	}
 	return dataCommitmentEvents, nil