diff --git a/src/dsnotificationinterface.cpp b/src/dsnotificationinterface.cpp
index 954de50d0..418f1f9e2 100644
--- a/src/dsnotificationinterface.cpp
+++ b/src/dsnotificationinterface.cpp
@@ -71,9 +71,15 @@ void CDSNotificationInterface::UpdatedBlockTip(const CBlockIndex *pindexNew, con
     llmq::quorumDKGSessionManager->UpdatedBlockTip(pindexNew, pindexFork, fInitialDownload);
 }
 
+void CDSNotificationInterface::NewPoWValidBlock(const CBlockIndex* pindex, const std::shared_ptr<const CBlock>& block)
+{
+    llmq::chainLocksHandler->NewPoWValidBlock(pindex, block);
+}
+
 void CDSNotificationInterface::SyncTransaction(const CTransaction &tx, const CBlockIndex *pindex, int posInBlock)
 {
     llmq::quorumInstantSendManager->SyncTransaction(tx, pindex, posInBlock);
+    llmq::chainLocksHandler->SyncTransaction(tx, pindex, posInBlock);
     instantsend.SyncTransaction(tx, pindex, posInBlock);
     CPrivateSend::SyncTransaction(tx, pindex, posInBlock);
 }
diff --git a/src/dsnotificationinterface.h b/src/dsnotificationinterface.h
index f4e97d7ed..60c1e5bd3 100644
--- a/src/dsnotificationinterface.h
+++ b/src/dsnotificationinterface.h
@@ -21,6 +21,7 @@ protected:
     void AcceptedBlockHeader(const CBlockIndex *pindexNew) override;
     void NotifyHeaderTip(const CBlockIndex *pindexNew, bool fInitialDownload) override;
     void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) override;
+    void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& block) override;
     void SyncTransaction(const CTransaction &tx, const CBlockIndex *pindex, int posInBlock) override;
     void NotifyMasternodeListChanged(const CDeterministicMNList& newList) override;
     void NotifyChainLock(const CBlockIndex* pindex);
diff --git a/src/llmq/quorums_chainlocks.cpp b/src/llmq/quorums_chainlocks.cpp
index 5a51f98e9..67c9ddbef 100644
--- a/src/llmq/quorums_chainlocks.cpp
+++ b/src/llmq/quorums_chainlocks.cpp
@@ -11,6 +11,7 @@
 #include "net_processing.h"
 #include "scheduler.h"
 #include "spork.h"
+#include "txmempool.h"
 #include "validation.h"
 
 namespace llmq
@@ -244,6 +245,51 @@ void CChainLocksHandler::UpdatedBlockTip(const CBlockIndex* pindexNew, const CBl
     quorumSigningManager->AsyncSignIfMember(Params().GetConsensus().llmqChainLocks, requestId, msgHash);
 }
 
+void CChainLocksHandler::NewPoWValidBlock(const CBlockIndex* pindex, const std::shared_ptr<const CBlock>& block)
+{
+    LOCK(cs);
+    if (blockTxs.count(pindex->GetBlockHash())) {
+        // should actually not happen (blocks are only written once to disk and this is when NewPoWValidBlock is called)
+        // but be extra safe here in case this behaviour changes.
+        return;
+    }
+
+    // We listen for NewPoWValidBlock so that we can collect all TX ids of all included TXs of newly received blocks
+    // We need this information later when we try to sign a new tip, so that we can determine if all included TXs are
+    // safe.
+
+    auto txs = std::make_shared<std::unordered_set<uint256, StaticSaltedHasher>>();
+    for (const auto& tx : block->vtx) {
+        if (tx->nVersion == 3) {
+            if (tx->nType == TRANSACTION_COINBASE ||
+                tx->nType == TRANSACTION_QUORUM_COMMITMENT) {
+                continue;
+            }
+        }
+        txs->emplace(tx->GetHash());
+    }
+    blockTxs[pindex->GetBlockHash()] = txs;
+
+    int64_t curTime = GetAdjustedTime();
+    for (auto& tx : block->vtx) {
+        txFirstSeenTime.emplace(tx->GetHash(), curTime);
+    }
+}
+
+void CChainLocksHandler::SyncTransaction(const CTransaction& tx, const CBlockIndex* pindex, int posInBlock)
+{
+    if (tx.nVersion == 3) {
+        if (tx.nType == TRANSACTION_COINBASE ||
+            tx.nType == TRANSACTION_QUORUM_COMMITMENT) {
+            return;
+        }
+    }
+
+    LOCK(cs);
+    int64_t curTime = GetAdjustedTime();
+    txFirstSeenTime.emplace(tx.GetHash(), curTime);
+}
+
 // WARNING: cs_main and cs should not be held!
 void CChainLocksHandler::EnforceBestChainLock()
 {
@@ -420,7 +466,9 @@ void CChainLocksHandler::Cleanup()
         }
     }
 
-    LOCK2(cs_main, cs);
+    // need mempool.cs due to GetTransaction calls
+    LOCK2(cs_main, mempool.cs);
+    LOCK(cs);
 
     for (auto it = seenChainLocks.begin(); it != seenChainLocks.end(); ) {
         if (GetTimeMillis() - it->second >= CLEANUP_SEEN_TIMEOUT) {
@@ -430,6 +478,38 @@ void CChainLocksHandler::Cleanup()
         }
     }
 
+    for (auto it = blockTxs.begin(); it != blockTxs.end(); ) {
+        auto pindex = mapBlockIndex.at(it->first);
+        if (InternalHasChainLock(pindex->nHeight, pindex->GetBlockHash())) {
+            for (auto& txid : *it->second) {
+                txFirstSeenTime.erase(txid);
+            }
+            it = blockTxs.erase(it);
+        } else if (InternalHasConflictingChainLock(pindex->nHeight, pindex->GetBlockHash())) {
+            it = blockTxs.erase(it);
+        } else {
+            ++it;
+        }
+    }
+    for (auto it = txFirstSeenTime.begin(); it != txFirstSeenTime.end(); ) {
+        CTransactionRef tx;
+        uint256 hashBlock;
+        if (!GetTransaction(it->first, tx, Params().GetConsensus(), hashBlock)) {
+            // tx has vanished, probably due to conflicts
+            it = txFirstSeenTime.erase(it);
+        } else if (!hashBlock.IsNull()) {
+            auto pindex = mapBlockIndex.at(hashBlock);
+            if (chainActive.Tip()->GetAncestor(pindex->nHeight) == pindex && chainActive.Height() - pindex->nHeight >= 6) {
+                // tx got confirmed >= 6 times, so we can stop keeping track of it
+                it = txFirstSeenTime.erase(it);
+            } else {
+                ++it;
+            }
+        } else {
+            ++it;
+        }
+    }
+
     lastCleanupTime = GetTimeMillis();
 }
 
diff --git a/src/llmq/quorums_chainlocks.h b/src/llmq/quorums_chainlocks.h
index b7cd441e0..410f2bf80 100644
--- a/src/llmq/quorums_chainlocks.h
+++ b/src/llmq/quorums_chainlocks.h
@@ -12,6 +12,7 @@
 #include "chainparams.h"
 
 #include <atomic>
+#include <unordered_set>
 
 class CBlockIndex;
 class CScheduler;
@@ -61,6 +62,10 @@ private:
     uint256 lastSignedRequestId;
     uint256 lastSignedMsgHash;
 
+    // We keep track of txids from recently received blocks so that we can check if all TXs got ixlocked
+    std::unordered_map<uint256, std::shared_ptr<std::unordered_set<uint256, StaticSaltedHasher>>> blockTxs;
+    std::unordered_map<uint256, int64_t> txFirstSeenTime;
+
     std::map<uint256, int64_t> seenChainLocks;
 
     int64_t lastCleanupTime{0};
@@ -79,6 +84,8 @@ public:
     void ProcessNewChainLock(NodeId from, const CChainLockSig& clsig, const uint256& hash);
     void AcceptedBlockHeader(const CBlockIndex* pindexNew);
     void UpdatedBlockTip(const CBlockIndex* pindexNew, const CBlockIndex* pindexFork);
+    void NewPoWValidBlock(const CBlockIndex* pindex, const std::shared_ptr<const CBlock>& block);
+    void SyncTransaction(const CTransaction &tx, const CBlockIndex *pindex, int posInBlock);
     void EnforceBestChainLock();
     virtual void HandleNewRecoveredSig(const CRecoveredSig& recoveredSig);