diff --git a/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/blockchain.ts b/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/blockchain.ts
index fe7dbd62c..770122f92 100644
--- a/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/blockchain.ts
+++ b/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/blockchain.ts
@@ -4,10 +4,8 @@ import {
   GradidoTransaction,
   HieroAccountId,
   InMemoryBlockchain,
-  InMemoryBlockchainProvider,
   LedgerAnchor,
   Profiler,
-  TransactionEntry,
 } from 'gradido-blockchain-js'
 import { NotEnoughGradidoBalanceError } from './errors'
 
@@ -21,10 +19,9 @@ export function addToBlockchain(
   ledgerAnchor: LedgerAnchor,
   accountBalances: AccountBalances,
 ): boolean {
-  
   try {    
     timeUsed.reset()
-    const result = blockchain.createAndAddConfirmedTransactionExtern(
+    const result = blockchain.createAndAddConfirmedTransactionExternFast(
       transaction,
       ledgerAnchor,
       accountBalances,
diff --git a/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/index.ts b/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/index.ts
index cb8e99af3..aa418625d 100644
--- a/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/index.ts
+++ b/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/index.ts
@@ -2,7 +2,8 @@ import { onShutdown } from '../../../../shared/src/helper/onShutdown'
 import { exportAllCommunities } from './binaryExport'
 import { bootstrap } from './bootstrap'
 import { syncDbWithBlockchainContext } from './interaction/syncDbWithBlockchain/syncDbWithBlockchain.context'
-// import { hello } from '../../../zig/hello.zig'
+import { Filter, Profiler, ThreadingPolicy_Half, verifySignatures } from 'gradido-blockchain-js'
+  // import { hello } from '../../../zig/hello.zig'
 
 const BATCH_SIZE = 1000
 
@@ -26,6 +27,17 @@ async function main() {
     //context.logBlogchain(v.parse(uuidv4Schema, 'e70da33e-5976-4767-bade-aa4e4fa1c01a'))
   }
 
+  const timeUsed = new Profiler()
+  // bulk verify transaction signatures
+  for (const communityContext of context.communities.values()) {
+    // verifySignatures(Filter.ALL_TRANSACTIONS, ThreadingPolicy_Half)
+    const result = verifySignatures(Filter.ALL_TRANSACTIONS, communityContext.communityId, ThreadingPolicy_Half)
+    if(!result.isEmpty()){
+      throw new Error(`Verification of signatures failed for community ${communityContext.communityId}`)
+    }
+  }
+  context.logger.info(`verified in ${timeUsed.string()}`)
+
   // write as binary file for GradidoNode
   exportAllCommunities(context, BATCH_SIZE)
 
diff --git a/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/interaction/syncDbWithBlockchain/RemoteTransactionsSync.role.ts b/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/interaction/syncDbWithBlockchain/RemoteTransactionsSync.role.ts
index d2d01925a..712119378 100644
--- a/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/interaction/syncDbWithBlockchain/RemoteTransactionsSync.role.ts
+++ b/dlt-connector/src/migrations/db-v2.7.0_to_blockchain-v3.7/interaction/syncDbWithBlockchain/RemoteTransactionsSync.role.ts
@@ -165,9 +165,6 @@ export class RemoteTransactionsSyncRole extends AbstractSyncRole<TransactionDb>
       recipientCommunityContext.communityId
     )
     const outboundTransaction = transactionBuilder.buildOutbound()
-    console.log(ledgerAnchor.toJson(true))
-    console.log(outboundTransaction.toJson(true))
-    console.log("outbound coin color: %d", outboundTransaction.getTransactionBody()?.getTransferAmount().getCoinCommunityIdIndex())
 
     try {
       addToBlockchain(
@@ -184,8 +181,6 @@ export class RemoteTransactionsSyncRole extends AbstractSyncRole<TransactionDb>
     }
     transactionBuilder.setParentLedgerAnchor(ledgerAnchor)
     const inboundTransaction = transactionBuilder.buildInbound()
-    console.log(inboundTransaction.toJson(true))
-    console.log("inbound coin color: %d", inboundTransaction.getTransactionBody()?.getTransferAmount().getCoinCommunityIdIndex())
     try {
       addToBlockchain(
         inboundTransaction,