diff --git a/src/avalanche/peermanager.h b/src/avalanche/peermanager.h
--- a/src/avalanche/peermanager.h
+++ b/src/avalanche/peermanager.h
@@ -164,6 +164,9 @@
      */
     std::unordered_set<ProofId, SaltedProofIdHasher> m_unbroadcast_proofids;
 
+    std::unordered_map<ProofId, std::chrono::seconds, SaltedProofIdHasher>
+        nextPossibleConflictTime;
+
 public:
     /**
      * Node API.
@@ -195,6 +198,14 @@
     /**
      * Proof and Peer related API.
      */
+
+    /**
+     * Update the time before which a proof conflicting with the one with the
+     * given proofid will be rejected.
+     */
+    bool updateNextPossibleConflictTime(const ProofId &proofid,
+                                        const std::chrono::seconds &nextTime);
+
     bool registerProof(const ProofRef &proof);
     bool exists(const ProofId &proofid) const {
         return getProof(proofid) != nullptr;
diff --git a/src/avalanche/peermanager.cpp b/src/avalanche/peermanager.cpp
--- a/src/avalanche/peermanager.cpp
+++ b/src/avalanche/peermanager.cpp
@@ -147,6 +147,20 @@
            state.GetResult() == ProofValidationResult::HEIGHT_MISMATCH;
 }
 
+bool PeerManager::updateNextPossibleConflictTime(
+    const ProofId &proofid, const std::chrono::seconds &nextTime) {
+    // If there is no entry for this proofid, it will be created
+    // with the default value of 0, which is fine because it is
+    // far in the past.
+    auto &proofNextConflictTime = nextPossibleConflictTime[proofid];
+
+    // Update the next possible conflict time for this proof. Make sure we don't
+    // move the time in the past.
+    proofNextConflictTime = std::max(proofNextConflictTime, nextTime);
+
+    return proofNextConflictTime == nextTime;
+}
+
 bool PeerManager::registerProof(const ProofRef &proof) {
     assert(proof);
 
diff --git a/src/avalanche/test/peermanager_tests.cpp b/src/avalanche/test/peermanager_tests.cpp
--- a/src/avalanche/test/peermanager_tests.cpp
+++ b/src/avalanche/test/peermanager_tests.cpp
@@ -40,6 +40,11 @@
             auto it = pview.find(proof->getId());
             return it == pview.end() ? NO_PEER : it->peerid;
         }
+
+        static std::chrono::seconds
+        getNextPossibleConflictTime(PeerManager &pm, const ProofId &proofid) {
+            return pm.nextPossibleConflictTime[proofid];
+        }
     };
 } // namespace
 } // namespace avalanche
@@ -1062,4 +1067,32 @@
     BOOST_CHECK(!pm.exists(proofSeq10->getId()));
 }
 
+BOOST_AUTO_TEST_CASE(update_next_conflict_time) {
+    avalanche::PeerManager pm;
+
+    const ProofId proofid{GetRandHash()};
+
+    auto checkNextPossibleConflictTime = [&](std::chrono::seconds expected) {
+        // FIXME: we can't use BOOST_CHECK_EQUAL without defining operator<< for
+        // std::chrono::duration
+        BOOST_CHECK(TestPeerManager::getNextPossibleConflictTime(pm, proofid) ==
+                    expected);
+    };
+
+    checkNextPossibleConflictTime(std::chrono::seconds{0});
+
+    auto now = GetTime<std::chrono::seconds>();
+    BOOST_CHECK(pm.updateNextPossibleConflictTime(proofid, now));
+    checkNextPossibleConflictTime(now);
+
+    // Move the time in the past is not possible
+    BOOST_CHECK(!pm.updateNextPossibleConflictTime(
+        proofid, now - std::chrono::seconds{1}));
+    checkNextPossibleConflictTime(now);
+
+    BOOST_CHECK(pm.updateNextPossibleConflictTime(
+        proofid, now + std::chrono::seconds{1}));
+    checkNextPossibleConflictTime(now + std::chrono::seconds{1});
+}
+
 BOOST_AUTO_TEST_SUITE_END()