diff --git a/src/main.cpp b/src/main.cpp
index 39d68af37..3035a3e5d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3310,12 +3310,18 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIn
     const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;
     const Consensus::Params& consensusParams = Params().GetConsensus();
 
+    // Start enforcing BIP113 (Median Time Past) using versionbits logic.
+    int nLockTimeFlags = 0;
+    if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
+        nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
+    }
+
+    int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
+                              ? pindexPrev->GetMedianTimePast()
+                              : block.GetBlockTime();
+
     // Check that all transactions are finalized
     BOOST_FOREACH(const CTransaction& tx, block.vtx) {
-        int nLockTimeFlags = 0;
-        int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
-                                ? pindexPrev->GetMedianTimePast()
-                                : block.GetBlockTime();
         if (!IsFinalTx(tx, nHeight, nLockTimeCutoff)) {
             return state.DoS(10, error("%s: contains a non-final transaction", __func__), REJECT_INVALID, "bad-txns-nonfinal");
         }