SERVER-36050 Remove isV1ElectionProtocol() check.

29 files changed, 91 insertions, 212 deletions

diff --git a/src/mongo/db/commands/get_last_error.cpp b/src/mongo/db/commands/get_last_error.cpp
index abeb8ed2220..e9ca375d880 100644
--- a/src/mongo/db/commands/get_last_error.cpp
+++ b/src/mongo/db/commands/get_last_error.cpp
@@ -151,11 +151,7 @@ public:
         if (replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet) {
             const repl::OpTime lastOp = repl::ReplClientInfo::forClient(c).getLastOp();
             if (!lastOp.isNull()) {
-                if (replCoord->isV1ElectionProtocol()) {
-                    lastOp.append(&result, "lastOp");
-                } else {
-                    result.append("lastOp", lastOp.getTimestamp());
-                }
+                lastOp.append(&result, "lastOp");
             }
         }
 
diff --git a/src/mongo/db/read_concern.cpp b/src/mongo/db/read_concern.cpp
index b8215af1610..fef22f8ab1f 100644
--- a/src/mongo/db/read_concern.cpp
+++ b/src/mongo/db/read_concern.cpp
@@ -231,14 +231,6 @@ Status waitForReadConcern(OperationContext* opCtx,
                     "node needs to be a replica set member to use read concern"};
         }
 
-        // Replica sets running pv0 do not support linearizable read concern until further testing
-        // is completed (SERVER-27025).
-        if (!replCoord->isV1ElectionProtocol()) {
-            return {
-                ErrorCodes::IncompatibleElectionProtocol,
-                "Replica sets running protocol version 0 do not support readConcern: linearizable"};
-        }
-
         if (readConcernArgs.getArgsOpTime()) {
             return {ErrorCodes::FailedToParse,
                     "afterOpTime not compatible with linearizable read concern"};
@@ -303,11 +295,6 @@ Status waitForReadConcern(OperationContext* opCtx,
             return {ErrorCodes::NotAReplicaSet,
                     "node needs to be a replica set member to use readConcern: snapshot"};
         }
-
-        if (!replCoord->isV1ElectionProtocol()) {
-            return {ErrorCodes::IncompatibleElectionProtocol,
-                    "Replica sets running protocol version 0 do not support readConcern: snapshot"};
-        }
         if (speculative) {
             session->setSpeculativeTransactionOpTimeToLastApplied(opCtx);
         }
@@ -325,11 +312,6 @@ Status waitForReadConcern(OperationContext* opCtx,
          readConcernArgs.getLevel() == repl::ReadConcernLevel::kSnapshotReadConcern) &&
         !speculative &&
         replCoord->getReplicationMode() == repl::ReplicationCoordinator::Mode::modeReplSet) {
-        if (!replCoord->isV1ElectionProtocol()) {
-            return {ErrorCodes::IncompatibleElectionProtocol,
-                    str::stream() << "Replica sets running protocol version 0 do not support "
-                                     "majority committed reads"};
-        }
 
         const int debugLevel = serverGlobalParams.clusterRole == ClusterRole::ConfigServer ? 1 : 2;
 
diff --git a/src/mongo/db/repl/data_replicator_external_state_impl.cpp b/src/mongo/db/repl/data_replicator_external_state_impl.cpp
index 25d717f1a2b..8c94f9e3b06 100644
--- a/src/mongo/db/repl/data_replicator_external_state_impl.cpp
+++ b/src/mongo/db/repl/data_replicator_external_state_impl.cpp
@@ -82,9 +82,6 @@ executor::TaskExecutor* DataReplicatorExternalStateImpl::getTaskExecutor() const
 }
 
 OpTimeWithTerm DataReplicatorExternalStateImpl::getCurrentTermAndLastCommittedOpTime() {
-    if (!_replicationCoordinator->isV1ElectionProtocol()) {
-        return {OpTime::kUninitializedTerm, OpTime()};
-    }
     return {_replicationCoordinator->getTerm(), _replicationCoordinator->getLastCommittedOpTime()};
 }
 
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index 42f471bedd4..061285a3227 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -152,8 +152,7 @@ void _getNextOpTimes(OperationContext* opCtx,
     long long term = OpTime::kUninitializedTerm;
 
     // Fetch term out of the newOpMutex.
-    if (replCoord->getReplicationMode() == ReplicationCoordinator::modeReplSet &&
-        replCoord->isV1ElectionProtocol()) {
+    if (replCoord->getReplicationMode() == ReplicationCoordinator::modeReplSet) {
         // Current term. If we're not a replset of pv=1, it remains kOldProtocolVersionTerm.
         term = replCoord->getTerm();
     }
diff --git a/src/mongo/db/repl/oplog_fetcher.cpp b/src/mongo/db/repl/oplog_fetcher.cpp
index 28af2d5a834..6545bace758 100644
--- a/src/mongo/db/repl/oplog_fetcher.cpp
+++ b/src/mongo/db/repl/oplog_fetcher.cpp
@@ -102,10 +102,7 @@ BSONObj makeGetMoreCommandObject(const NamespaceString& nss,
 /**
  * Returns command metadata object suitable for tailing remote oplog.
  */
-BSONObj makeMetadataObject(bool isV1ElectionProtocol) {
-    if (!isV1ElectionProtocol)
-        return ReadPreferenceSetting::secondaryPreferredMetadata();
-
+BSONObj makeMetadataObject() {
     BSONObjBuilder metaBuilder;
     metaBuilder << rpc::kReplSetMetadataFieldName << 1;
     metaBuilder << rpc::kOplogQueryMetadataFieldName << 1;
@@ -332,7 +329,7 @@ OplogFetcher::OplogFetcher(executor::TaskExecutor* executor,
                            maxFetcherRestarts,
                            onShutdownCallbackFn,
                            "oplog fetcher"),
-      _metadataObject(makeMetadataObject(config.getProtocolVersion() == 1LL)),
+      _metadataObject(makeMetadataObject()),
       _requiredRBID(requiredRBID),
       _requireFresherSyncSource(requireFresherSyncSource),
       _dataReplicatorExternalState(dataReplicatorExternalState),
diff --git a/src/mongo/db/repl/repl_set_commands.cpp b/src/mongo/db/repl/repl_set_commands.cpp
index da433b4a7e1..b01d30f8d4e 100644
--- a/src/mongo/db/repl/repl_set_commands.cpp
+++ b/src/mongo/db/repl/repl_set_commands.cpp
@@ -670,7 +670,7 @@ public:
         ReplSetHeartbeatResponse response;
         status = ReplicationCoordinator::get(opCtx)->processHeartbeatV1(args, &response);
         if (status.isOK())
-            response.addToBSON(&result, true);
+            response.addToBSON(&result);
 
         LOG_FOR_HEARTBEATS(2) << "Processed heartbeat from " << cmdObj.getStringField("from")
                               << " and generated response, " << response;
diff --git a/src/mongo/db/repl/repl_set_heartbeat_response.cpp b/src/mongo/db/repl/repl_set_heartbeat_response.cpp
index fa08f5d2aa0..040d43e0083 100644
--- a/src/mongo/db/repl/repl_set_heartbeat_response.cpp
+++ b/src/mongo/db/repl/repl_set_heartbeat_response.cpp
@@ -63,7 +63,7 @@ const std::string kTimestampFieldName = "ts";
 
 }  // namespace
 
-void ReplSetHeartbeatResponse::addToBSON(BSONObjBuilder* builder, bool isProtocolVersionV1) const {
+void ReplSetHeartbeatResponse::addToBSON(BSONObjBuilder* builder) const {
     builder->append(kOkFieldName, 1.0);
     if (_electionTimeSet) {
         builder->appendDate(kElectionTimeFieldName,
@@ -95,18 +95,13 @@ void ReplSetHeartbeatResponse::addToBSON(BSONObjBuilder* builder, bool isProtoco
         _durableOpTime.append(builder, kDurableOpTimeFieldName);
     }
     if (_appliedOpTimeSet) {
-        if (isProtocolVersionV1) {
-            _appliedOpTime.append(builder, kAppliedOpTimeFieldName);
-        } else {
-            builder->appendDate(kAppliedOpTimeFieldName,
-                                Date_t::fromMillisSinceEpoch(_appliedOpTime.getTimestamp().asLL()));
-        }
+        _appliedOpTime.append(builder, kAppliedOpTimeFieldName);
     }
 }
 
-BSONObj ReplSetHeartbeatResponse::toBSON(bool isProtocolVersionV1) const {
+BSONObj ReplSetHeartbeatResponse::toBSON() const {
     BSONObjBuilder builder;
-    addToBSON(&builder, isProtocolVersionV1);
+    addToBSON(&builder);
     return builder.obj();
 }
 
diff --git a/src/mongo/db/repl/repl_set_heartbeat_response.h b/src/mongo/db/repl/repl_set_heartbeat_response.h
index 5fe978d0d15..102a64ecf1a 100644
--- a/src/mongo/db/repl/repl_set_heartbeat_response.h
+++ b/src/mongo/db/repl/repl_set_heartbeat_response.h
@@ -57,18 +57,18 @@ public:
     /**
      * Appends all non-default values to "builder".
      */
-    void addToBSON(BSONObjBuilder* builder, bool isProtocolVersionV1) const;
+    void addToBSON(BSONObjBuilder* builder) const;
 
     /**
      * Returns a BSONObj consisting of all non-default values to "builder".
      */
-    BSONObj toBSON(bool isProtocolVersionV1) const;
+    BSONObj toBSON() const;
 
     /**
      * Returns toBSON().toString()
      */
     const std::string toString() const {
-        return toBSON(true).toString();
+        return toBSON().toString();
     }
 
     const std::string& getReplicaSetName() const {
diff --git a/src/mongo/db/repl/repl_set_heartbeat_response_test.cpp b/src/mongo/db/repl/repl_set_heartbeat_response_test.cpp
index 943da9d0246..7be7e94e667 100644
--- a/src/mongo/db/repl/repl_set_heartbeat_response_test.cpp
+++ b/src/mongo/db/repl/repl_set_heartbeat_response_test.cpp
@@ -57,7 +57,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(HostAndPort(), hbResponse.getSyncingTo());
     ASSERT_EQUALS(-1, hbResponse.getConfigVersion());
 
-    BSONObj hbResponseObj = hbResponse.toBSON(false);
+    BSONObj hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
 
@@ -77,7 +77,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(HostAndPort(), hbResponse.getSyncingTo());
     ASSERT_EQUALS(1, hbResponse.getConfigVersion());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
     ASSERT_EQUALS(1, hbResponseObj["v"].Number());
@@ -99,7 +99,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(HostAndPort(), hbResponse.getSyncingTo());
     ASSERT_EQUALS(1, hbResponse.getConfigVersion());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
@@ -123,7 +123,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(1, hbResponse.getConfigVersion());
     ASSERT_EQUALS(Timestamp(10, 0), hbResponse.getElectionTime());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
@@ -149,7 +149,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(Timestamp(10, 0), hbResponse.getElectionTime());
     ASSERT_EQUALS(OpTime(Timestamp(0, 10), 0), hbResponse.getDurableOpTime());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
@@ -159,7 +159,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
 
     initializeResult = hbResponseObjRoundTripChecker.initialize(hbResponseObj, 0);
     ASSERT_EQUALS(Status::OK(), initializeResult);
-    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON(false).toString());
+    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON().toString());
 
     // set appliedOpTime
     hbResponse.setAppliedOpTime(OpTime(Timestamp(50), 0));
@@ -177,18 +177,18 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(OpTime(Timestamp(0, 10), 0), hbResponse.getDurableOpTime());
     ASSERT_EQUALS(OpTime(Timestamp(0, 50), 0), hbResponse.getAppliedOpTime());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
     ASSERT_EQUALS(1, hbResponseObj["v"].Number());
     ASSERT_EQUALS(Timestamp(10, 0), hbResponseObj["electionTime"].timestamp());
-    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"].timestamp());
+    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"]["ts"].timestamp());
     ASSERT_EQUALS(Timestamp(0, 10), hbResponseObj["durableOpTime"]["ts"].timestamp());
 
     initializeResult = hbResponseObjRoundTripChecker.initialize(hbResponseObj, 0);
     ASSERT_EQUALS(Status::OK(), initializeResult);
-    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON(false).toString());
+    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON().toString());
 
     // set config
     ReplSetConfig config;
@@ -208,19 +208,19 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(OpTime(Timestamp(0, 50), 0), hbResponse.getAppliedOpTime());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponse.getConfig().toBSON().toString());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
     ASSERT_EQUALS(1, hbResponseObj["v"].Number());
     ASSERT_EQUALS(Timestamp(10, 0), hbResponseObj["electionTime"].timestamp());
-    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"].timestamp());
+    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"]["ts"].timestamp());
     ASSERT_EQUALS(Timestamp(0, 10), hbResponseObj["durableOpTime"]["ts"].timestamp());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponseObj["config"].Obj().toString());
 
     initializeResult = hbResponseObjRoundTripChecker.initialize(hbResponseObj, 0);
     ASSERT_EQUALS(Status::OK(), initializeResult);
-    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON(false).toString());
+    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON().toString());
 
     // set state
     hbResponse.setState(MemberState(MemberState::RS_SECONDARY));
@@ -241,20 +241,20 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(OpTime(Timestamp(0, 50), 0), hbResponse.getAppliedOpTime());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponse.getConfig().toBSON().toString());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
     ASSERT_EQUALS(1, hbResponseObj["v"].Number());
     ASSERT_EQUALS(Timestamp(10, 0), hbResponseObj["electionTime"].timestamp());
-    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"].timestamp());
+    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"]["ts"].timestamp());
     ASSERT_EQUALS(Timestamp(0, 10), hbResponseObj["durableOpTime"]["ts"].timestamp());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponseObj["config"].Obj().toString());
     ASSERT_EQUALS(2, hbResponseObj["state"].numberLong());
 
     initializeResult = hbResponseObjRoundTripChecker.initialize(hbResponseObj, 0);
     ASSERT_EQUALS(Status::OK(), initializeResult);
-    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON(false).toString());
+    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON().toString());
 
     // set syncingTo
     hbResponse.setSyncingTo(HostAndPort("syncTarget"));
@@ -275,13 +275,13 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(OpTime(Timestamp(0, 50), 0), hbResponse.getAppliedOpTime());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponse.getConfig().toBSON().toString());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("", hbResponseObj["hbmsg"].String());
     ASSERT_EQUALS(1, hbResponseObj["v"].Number());
     ASSERT_EQUALS(Timestamp(10, 0), hbResponseObj["electionTime"].timestamp());
-    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"].timestamp());
+    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"]["ts"].timestamp());
     ASSERT_EQUALS(Timestamp(0, 10), hbResponseObj["durableOpTime"]["ts"].timestamp());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponseObj["config"].Obj().toString());
     ASSERT_EQUALS(2, hbResponseObj["state"].numberLong());
@@ -289,7 +289,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
 
     initializeResult = hbResponseObjRoundTripChecker.initialize(hbResponseObj, 0);
     ASSERT_EQUALS(Status::OK(), initializeResult);
-    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON(false).toString());
+    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON().toString());
 
     // set hbmsg
     hbResponse.setHbMsg("lub dub");
@@ -309,13 +309,13 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
     ASSERT_EQUALS(OpTime(Timestamp(0, 50), 0), hbResponse.getAppliedOpTime());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponse.getConfig().toBSON().toString());
 
-    hbResponseObj = hbResponse.toBSON(false);
+    hbResponseObj = hbResponse.toBSON();
     ASSERT_EQUALS(fieldsSet, hbResponseObj.nFields());
     ASSERT_EQUALS("rs0", hbResponseObj["set"].String());
     ASSERT_EQUALS("lub dub", hbResponseObj["hbmsg"].String());
     ASSERT_EQUALS(1, hbResponseObj["v"].Number());
     ASSERT_EQUALS(Timestamp(10, 0), hbResponseObj["electionTime"].timestamp());
-    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"].timestamp());
+    ASSERT_EQUALS(Timestamp(0, 50), hbResponseObj["opTime"]["ts"].timestamp());
     ASSERT_EQUALS(Timestamp(0, 10), hbResponseObj["durableOpTime"]["ts"].timestamp());
     ASSERT_EQUALS(config.toBSON().toString(), hbResponseObj["config"].Obj().toString());
     ASSERT_EQUALS(2, hbResponseObj["state"].numberLong());
@@ -323,7 +323,7 @@ TEST(ReplSetHeartbeatResponse, DefaultConstructThenSlowlyBuildToFullObj) {
 
     initializeResult = hbResponseObjRoundTripChecker.initialize(hbResponseObj, 0);
     ASSERT_EQUALS(Status::OK(), initializeResult);
-    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON(false).toString());
+    ASSERT_EQUALS(hbResponseObj.toString(), hbResponseObjRoundTripChecker.toBSON().toString());
 }
 
 TEST(ReplSetHeartbeatResponse, InitializeWrongElectionTimeType) {
diff --git a/src/mongo/db/repl/replication_coordinator.h b/src/mongo/db/repl/replication_coordinator.h
index b2f61698e88..2b75d7485fb 100644
--- a/src/mongo/db/repl/replication_coordinator.h
+++ b/src/mongo/db/repl/replication_coordinator.h
@@ -697,11 +697,6 @@ public:
                                      BSONObjBuilder* builder) const = 0;
 
     /**
-     * Returns true if the V1 election protocol is being used and false otherwise.
-     */
-    virtual bool isV1ElectionProtocol() const = 0;
-
-    /**
      * Returns whether or not majority write concerns should implicitly journal, if j has not been
      * explicitly set.
      */
diff --git a/src/mongo/db/repl/replication_coordinator_external_state.h b/src/mongo/db/repl/replication_coordinator_external_state.h
index e70f68f47a8..0972a377efd 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state.h
@@ -135,13 +135,12 @@ public:
      * state. See the call site in ReplicationCoordinatorImpl for details about when and how it is
      * called.
      *
-     * Among other things, this writes a message about our transition to primary to the oplog if
-     * isV1 and and returns the optime of that message. If !isV1, returns the optime of the last op
-     * in the oplog.
+     * Among other things, this writes a message about our transition to primary to the oplog and
+     * returns the optime of that message.
      *
      * Throws on errors.
      */
-    virtual OpTime onTransitionToPrimary(OperationContext* opCtx, bool isV1ElectionProtocol) = 0;
+    virtual OpTime onTransitionToPrimary(OperationContext* opCtx) = 0;
 
     /**
      * Simple wrapper around SyncSourceFeedback::forwardSlaveProgress.  Signals to the
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
index 20d96481ace..91345c4c304 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -483,8 +483,7 @@ void ReplicationCoordinatorExternalStateImpl::onDrainComplete(OperationContext*
     }
 }
 
-OpTime ReplicationCoordinatorExternalStateImpl::onTransitionToPrimary(OperationContext* opCtx,
-                                                                      bool isV1ElectionProtocol) {
+OpTime ReplicationCoordinatorExternalStateImpl::onTransitionToPrimary(OperationContext* opCtx) {
     invariant(opCtx->lockState()->isW());
 
     // Clear the appliedThrough marker so on startup we'll use the top of the oplog. This must be
@@ -498,16 +497,14 @@ OpTime ReplicationCoordinatorExternalStateImpl::onTransitionToPrimary(OperationC
     _replicationProcess->getConsistencyMarkers()->clearAppliedThrough(
         opCtx, lastAppliedOpTime.getTimestamp());
 
-    if (isV1ElectionProtocol) {
-        writeConflictRetry(opCtx, "logging transition to primary to oplog", "local.oplog.rs", [&] {
-            WriteUnitOfWork wuow(opCtx);
-            opCtx->getClient()->getServiceContext()->getOpObserver()->onOpMessage(
-                opCtx,
-                BSON("msg"
-                     << "new primary"));
-            wuow.commit();
-        });
-    }
+    writeConflictRetry(opCtx, "logging transition to primary to oplog", "local.oplog.rs", [&] {
+        WriteUnitOfWork wuow(opCtx);
+        opCtx->getClient()->getServiceContext()->getOpObserver()->onOpMessage(
+            opCtx,
+            BSON("msg"
+                 << "new primary"));
+        wuow.commit();
+    });
     const auto opTimeToReturn = fassert(28665, loadLastOpTime(opCtx));
 
     _shardingOnTransitionToPrimaryHook(opCtx);
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.h b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
index 797175b8111..4f8be81a4ba 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
@@ -79,7 +79,7 @@ public:
     virtual Status initializeReplSetStorage(OperationContext* opCtx, const BSONObj& config);
     virtual void waitForAllEarlierOplogWritesToBeVisible(OperationContext* opCtx);
     void onDrainComplete(OperationContext* opCtx) override;
-    OpTime onTransitionToPrimary(OperationContext* opCtx, bool isV1ElectionProtocol) override;
+    OpTime onTransitionToPrimary(OperationContext* opCtx) override;
     virtual void forwardSlaveProgress();
     virtual bool isSelf(const HostAndPort& host, ServiceContext* service);
     virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* opCtx);
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
index 30568571626..842fcf4fd27 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
@@ -262,8 +262,7 @@ void ReplicationCoordinatorExternalStateMock::setIsReadCommittedEnabled(bool val
 
 void ReplicationCoordinatorExternalStateMock::onDrainComplete(OperationContext* opCtx) {}
 
-OpTime ReplicationCoordinatorExternalStateMock::onTransitionToPrimary(OperationContext* opCtx,
-                                                                      bool isV1ElectionProtocol) {
+OpTime ReplicationCoordinatorExternalStateMock::onTransitionToPrimary(OperationContext* opCtx) {
     _lastOpTime = _firstOpTimeOfMyTerm;
     _firstOpTimeOfMyTerm = OpTime();
     return fassert(40297, _lastOpTime);
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_mock.h b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
index 05d08eb0f6d..84e615280dd 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
@@ -68,7 +68,7 @@ public:
     virtual Status initializeReplSetStorage(OperationContext* opCtx, const BSONObj& config);
     virtual void waitForAllEarlierOplogWritesToBeVisible(OperationContext* opCtx);
     void onDrainComplete(OperationContext* opCtx) override;
-    OpTime onTransitionToPrimary(OperationContext* opCtx, bool isV1ElectionProtocol) override;
+    OpTime onTransitionToPrimary(OperationContext* opCtx) override;
     virtual void forwardSlaveProgress();
     virtual bool isSelf(const HostAndPort& host, ServiceContext* service);
     virtual HostAndPort getClientHostAndPort(const OperationContext* opCtx);
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index a80bc8885f2..184b848b700 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -996,7 +996,7 @@ void ReplicationCoordinatorImpl::signalDrainComplete(OperationContext* opCtx,
     {
         lk.unlock();
         AllowNonLocalWritesBlock writesAllowed(opCtx);
-        OpTime firstOpTime = _externalState->onTransitionToPrimary(opCtx, isV1ElectionProtocol());
+        OpTime firstOpTime = _externalState->onTransitionToPrimary(opCtx);
         lk.lock();
 
         auto status = _topCoord->completeTransitionToPrimary(firstOpTime);
@@ -1819,7 +1819,6 @@ void ReplicationCoordinatorImpl::_handleTimePassing(
 
     // For election protocol v1, call _startElectSelfIfEligibleV1 to avoid race
     // against other elections caused by events like election timeout, replSetStepUp etc.
-    invariant(isV1ElectionProtocol());
     _startElectSelfIfEligibleV1(
         TopologyCoordinator::StartElectionReason::kSingleNodeStepDownTimeout);
 }
@@ -2460,11 +2459,8 @@ ReplicationCoordinatorImpl::_updateMemberStateFromTopologyCoordinator_inlock(
         if (_topCoord->getRole() == TopologyCoordinator::Role::kCandidate) {
             invariant(_rsConfig.getNumMembers() == 1 && _selfIndex == 0 &&
                       _rsConfig.getMemberAt(0).isElectable());
-            if (isV1ElectionProtocol()) {
-                // Start election in protocol version 1
-                return kActionStartSingleNodeElection;
-            }
-            return kActionWinElection;
+            // Start election in protocol version 1
+            return kActionStartSingleNodeElection;
         }
         return kActionNone;
     }
@@ -2508,12 +2504,8 @@ ReplicationCoordinatorImpl::_updateMemberStateFromTopologyCoordinator_inlock(
         // overriding requirement is to elect this singleton node primary.
         invariant(_rsConfig.getNumMembers() == 1 && _selfIndex == 0 &&
                   _rsConfig.getMemberAt(0).isElectable());
-        if (isV1ElectionProtocol()) {
-            // Start election in protocol version 1
-            result = kActionStartSingleNodeElection;
-        } else {
-            result = kActionWinElection;
-        }
+        // Start election in protocol version 1
+        result = kActionStartSingleNodeElection;
     }
 
     if (newState.rollback()) {
@@ -2593,12 +2585,8 @@ void ReplicationCoordinatorImpl::_performPostMemberStateUpdateAction(
             break;
         case kActionWinElection: {
             stdx::unique_lock<stdx::mutex> lk(_mutex);
-            if (isV1ElectionProtocol()) {
-                invariant(_topCoord->getTerm() != OpTime::kUninitializedTerm);
-                _electionId = OID::fromTerm(_topCoord->getTerm());
-            } else {
-                _electionId = OID::gen();
-            }
+            invariant(_topCoord->getTerm() != OpTime::kUninitializedTerm);
+            _electionId = OID::fromTerm(_topCoord->getTerm());
 
             auto ts = LogicalClock::get(getServiceContext())->reserveTicks(1).asTimestamp();
             _topCoord->processWinElection(_electionId, ts);
@@ -2613,13 +2601,9 @@ void ReplicationCoordinatorImpl::_performPostMemberStateUpdateAction(
             }
             // Notify all secondaries of the election win.
             _restartHeartbeats_inlock();
-            if (isV1ElectionProtocol()) {
-                invariant(!_catchupState);
-                _catchupState = stdx::make_unique<CatchupState>(this);
-                _catchupState->start_inlock();
-            } else {
-                _enterDrainMode_inlock();
-            }
+            invariant(!_catchupState);
+            _catchupState = stdx::make_unique<CatchupState>(this);
+            _catchupState->start_inlock();
             break;
         }
         case kActionStartSingleNodeElection:
@@ -2734,11 +2718,6 @@ void ReplicationCoordinatorImpl::CatchupState::signalHeartbeatUpdate_inlock() {
 }
 
 Status ReplicationCoordinatorImpl::abortCatchupIfNeeded() {
-    if (!isV1ElectionProtocol()) {
-        return Status(ErrorCodes::CommandNotSupported,
-                      "Primary catch-up is only supported by Protocol Version 1");
-    }
-
     stdx::lock_guard<stdx::mutex> lk(_mutex);
     if (_catchupState) {
         _catchupState->abort_inlock();
@@ -3179,9 +3158,6 @@ Status ReplicationCoordinatorImpl::processReplSetRequestVotes(
     OperationContext* opCtx,
     const ReplSetRequestVotesArgs& args,
     ReplSetRequestVotesResponse* response) {
-    if (!isV1ElectionProtocol()) {
-        return {ErrorCodes::BadValue, "not using election protocol v1"};
-    }
 
     auto termStatus = updateTerm(opCtx, args.getTerm());
     if (!termStatus.isOK() && termStatus.code() != ErrorCodes::StaleTerm)
@@ -3246,10 +3222,6 @@ void ReplicationCoordinatorImpl::_prepareOplogQueryMetadata_inlock(int rbid,
     _topCoord->prepareOplogQueryMetadata(rbid).writeToMetadata(builder).transitional_ignore();
 }
 
-bool ReplicationCoordinatorImpl::isV1ElectionProtocol() const {
-    return _protVersion.load() == 1;
-}
-
 bool ReplicationCoordinatorImpl::getWriteConcernMajorityShouldJournal() {
     return getConfig().getWriteConcernMajorityShouldJournal();
 }
@@ -3324,11 +3296,6 @@ Status ReplicationCoordinatorImpl::updateTerm(OperationContext* opCtx, long long
         return {ErrorCodes::BadValue, "cannot supply 'term' without active replication"};
     }
 
-    if (!isV1ElectionProtocol()) {
-        // Do not update if not in V1 protocol.
-        return Status::OK();
-    }
-
     // Check we haven't acquired any lock, because potential stepdown needs global lock.
     dassert(!opCtx->lockState()->isLocked() || opCtx->lockState()->isNoop());
     TopologyCoordinator::UpdateTermResult updateTermResult;
@@ -3353,10 +3320,6 @@ Status ReplicationCoordinatorImpl::updateTerm(OperationContext* opCtx, long long
 
 EventHandle ReplicationCoordinatorImpl::_updateTerm_inlock(
     long long term, TopologyCoordinator::UpdateTermResult* updateTermResult) {
-    if (!isV1ElectionProtocol()) {
-        LOG(3) << "Cannot update term in election protocol version 0";
-        return EventHandle();
-    }
 
     auto now = _replExecutor->now();
     TopologyCoordinator::UpdateTermResult localUpdateTermResult = _topCoord->updateTerm(term, now);
@@ -3527,11 +3490,6 @@ CallbackFn ReplicationCoordinatorImpl::_wrapAsCallbackFn(const stdx::function<vo
 }
 
 Status ReplicationCoordinatorImpl::stepUpIfEligible() {
-    if (!isV1ElectionProtocol()) {
-        return Status(ErrorCodes::CommandNotSupported,
-                      "Step-up command is only supported by Protocol Version 1");
-    }
-
     _startElectSelfIfEligibleV1(TopologyCoordinator::StartElectionReason::kStepUpRequest);
     EventHandle finishEvent;
     {
@@ -3563,7 +3521,6 @@ executor::TaskExecutor::EventHandle ReplicationCoordinatorImpl::_cancelElectionI
     if (_topCoord->getRole() != TopologyCoordinator::Role::kCandidate) {
         return {};
     }
-    invariant(isV1ElectionProtocol());
     invariant(_voteRequester);
     _voteRequester->cancel();
     return _electionFinishedEvent;
diff --git a/src/mongo/db/repl/replication_coordinator_impl.h b/src/mongo/db/repl/replication_coordinator_impl.h
index a0175b86458..33b9404f18f 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_impl.h
@@ -258,8 +258,6 @@ public:
     virtual Status processHeartbeatV1(const ReplSetHeartbeatArgsV1& args,
                                       ReplSetHeartbeatResponse* response) override;
 
-    virtual bool isV1ElectionProtocol() const override;
-
     virtual bool getWriteConcernMajorityShouldJournal() override;
 
     virtual void summarizeAsHtml(ReplSetHtmlSummary* s) override;
diff --git a/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp
index 388c465e69d..ff6335916ce 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp
@@ -495,7 +495,7 @@ TEST_F(ReplCoordTest, NodeWillNotStandForElectionDuringHeartbeatReconfig) {
     hbResp2.setState(MemberState::RS_SECONDARY);
     net->runUntil(net->now() + Seconds(10));  // run until we've sent a heartbeat request
     const NetworkInterfaceMock::NetworkOperationIterator noi2 = net->getNextReadyRequest();
-    net->scheduleResponse(noi2, net->now(), makeResponseStatus(hbResp2.toBSON(true)));
+    net->scheduleResponse(noi2, net->now(), makeResponseStatus(hbResp2.toBSON()));
     net->runReadyNetworkOperations();
     getNet()->exitNetwork();
 
@@ -525,7 +525,7 @@ TEST_F(ReplCoordTest, NodeWillNotStandForElectionDuringHeartbeatReconfig) {
             hbResp.setState(MemberState::RS_SECONDARY);
             hbResp.setConfigVersion(rsConfig.getConfigVersion());
             BSONObjBuilder respObj;
-            net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true)));
+            net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON()));
         } else {
             error() << "Black holing unexpected request to " << request.target << ": "
                     << request.cmdObj;
@@ -943,7 +943,7 @@ private:
             hbResp.setTerm(replCoord->getTerm());
             hbResp.setAppliedOpTime(otherNodesOpTime);
             hbResp.setDurableOpTime(otherNodesOpTime);
-            auto response = makeResponseStatus(hbResp.toBSON(replCoord->isV1ElectionProtocol()));
+            auto response = makeResponseStatus(hbResp.toBSON());
             net->scheduleResponse(noi, net->now(), response);
         }
     }
@@ -2110,7 +2110,7 @@ protected:
         hbResp.setConfigVersion(rsConfig.getConfigVersion());
         hbResp.setAppliedOpTime(opTime);
         hbResp.setDurableOpTime(opTime);
-        return makeResponseStatus(hbResp.toBSON(true));
+        return makeResponseStatus(hbResp.toBSON());
     }
 
     void simulateSuccessfulV1Voting() {
diff --git a/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp b/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp
index d1269f78d1b..bfa7d03cb68 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp
@@ -95,7 +95,6 @@ void ReplicationCoordinatorImpl::_doMemberHeartbeat(executor::TaskExecutor::Call
     const Date_t now = _replExecutor->now();
     BSONObj heartbeatObj;
     Milliseconds timeout(0);
-    invariant(isV1ElectionProtocol());
     const std::pair<ReplSetHeartbeatArgsV1, Milliseconds> hbRequest =
         _topCoord->prepareHeartbeatRequestV1(now, _settings.ourSetName(), target);
     heartbeatObj = hbRequest.first.toBSON();
@@ -661,10 +660,8 @@ void ReplicationCoordinatorImpl::_startHeartbeats_inlock() {
 
     _topCoord->restartHeartbeats();
 
-    if (isV1ElectionProtocol()) {
-        _topCoord->resetAllMemberTimeouts(_replExecutor->now());
-        _scheduleNextLivenessUpdate_inlock();
-    }
+    _topCoord->resetAllMemberTimeouts(_replExecutor->now());
+    _scheduleNextLivenessUpdate_inlock();
 }
 
 void ReplicationCoordinatorImpl::_handleLivenessTimeout(
@@ -677,9 +674,6 @@ void ReplicationCoordinatorImpl::_handleLivenessTimeout(
     if (!cbData.status.isOK()) {
         return;
     }
-    if (!isV1ElectionProtocol()) {
-        return;
-    }
 
     // Scan liveness table for problems and mark nodes as down by calling into topocoord.
     HeartbeatResponseAction action = _topCoord->checkMemberTimeouts(_replExecutor->now());
@@ -692,9 +686,6 @@ void ReplicationCoordinatorImpl::_handleLivenessTimeout(
 }
 
 void ReplicationCoordinatorImpl::_scheduleNextLivenessUpdate_inlock() {
-    if (!isV1ElectionProtocol()) {
-        return;
-    }
     // Scan liveness table for earliest date; schedule a run at (that date plus election
     // timeout).
     Date_t earliestDate;
@@ -773,10 +764,6 @@ void ReplicationCoordinatorImpl::_cancelAndRescheduleElectionTimeout_inlock() {
         return;
     }
 
-    if (!isV1ElectionProtocol()) {
-        return;
-    }
-
     if (!_memberState.secondary()) {
         return;
     }
@@ -803,9 +790,6 @@ void ReplicationCoordinatorImpl::_cancelAndRescheduleElectionTimeout_inlock() {
 
 void ReplicationCoordinatorImpl::_startElectSelfIfEligibleV1(
     TopologyCoordinator::StartElectionReason reason) {
-    if (!isV1ElectionProtocol()) {
-        return;
-    }
     stdx::lock_guard<stdx::mutex> lock(_mutex);
     // If it is not a single node replica set, no need to start an election after stepdown timeout.
     if (reason == TopologyCoordinator::StartElectionReason::kSingleNodeStepDownTimeout &&
diff --git a/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp
index 05a9c1281fc..15d83b93eb3 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_heartbeat_v1_test.cpp
@@ -125,7 +125,7 @@ TEST_F(ReplCoordHBV1Test,
     hbResp.setConfig(rsConfig);
     BSONObjBuilder responseBuilder;
     responseBuilder << "ok" << 1;
-    hbResp.addToBSON(&responseBuilder, true);
+    hbResp.addToBSON(&responseBuilder);
     net->scheduleResponse(
         noi, startDate + Milliseconds(200), makeResponseStatus(responseBuilder.obj()));
     assertRunUntil(startDate + Milliseconds(200));
@@ -195,7 +195,7 @@ TEST_F(ReplCoordHBV1Test,
     hbResp.setConfig(rsConfig);
     BSONObjBuilder responseBuilder;
     responseBuilder << "ok" << 1;
-    hbResp.addToBSON(&responseBuilder, true);
+    hbResp.addToBSON(&responseBuilder);
     net->scheduleResponse(
         noi, startDate + Milliseconds(200), makeResponseStatus(responseBuilder.obj()));
     assertRunUntil(startDate + Milliseconds(200));
@@ -265,7 +265,7 @@ TEST_F(ReplCoordHBV1Test,
     hbResp.setConfig(rsConfig);
     BSONObjBuilder responseBuilder;
     responseBuilder << "ok" << 1;
-    hbResp.addToBSON(&responseBuilder, true);
+    hbResp.addToBSON(&responseBuilder);
     net->scheduleResponse(
         noi, startDate + Milliseconds(200), makeResponseStatus(responseBuilder.obj()));
     assertRunUntil(startDate + Milliseconds(2200));
@@ -376,7 +376,7 @@ TEST_F(ReplCoordHBV1Test, IgnoreTheContentsOfMetadataWhenItsReplicaSetIdDoesNotM
 
         BSONObjBuilder responseBuilder;
         responseBuilder << "ok" << 1;
-        hbResp.addToBSON(&responseBuilder, true);
+        hbResp.addToBSON(&responseBuilder);
 
         rpc::ReplSetMetadata metadata(
             opTime.getTerm(), opTime, opTime, rsConfig.getConfigVersion(), unexpectedId, 1, -1);
diff --git a/src/mongo/db/repl/replication_coordinator_impl_reconfig_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_reconfig_test.cpp
index 5aefac8a7b2..60e93ee965f 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_reconfig_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_reconfig_test.cpp
@@ -333,7 +333,7 @@ TEST_F(ReplCoordTest,
     hbResp.setConfigVersion(5);
     BSONObjBuilder respObj;
     respObj << "ok" << 1;
-    hbResp.addToBSON(&respObj, false);
+    hbResp.addToBSON(&respObj);
     net->scheduleResponse(noi, net->now(), makeResponseStatus(respObj.obj()));
     net->runReadyNetworkOperations();
     getNet()->exitNetwork();
@@ -492,7 +492,7 @@ TEST_F(ReplCoordTest, PrimaryNodeAcceptsNewConfigWhenReceivingAReconfigWithAComp
     hbResp.setConfigVersion(2);
     BSONObjBuilder respObj;
     respObj << "ok" << 1;
-    hbResp.addToBSON(&respObj, false);
+    hbResp.addToBSON(&respObj);
     net->scheduleResponse(noi, net->now(), makeResponseStatus(respObj.obj()));
     net->runReadyNetworkOperations();
     getNet()->exitNetwork();
@@ -549,7 +549,7 @@ TEST_F(
     hbResp2.setState(MemberState::RS_SECONDARY);
     BSONObjBuilder respObj2;
     respObj2 << "ok" << 1;
-    hbResp2.addToBSON(&respObj2, false);
+    hbResp2.addToBSON(&respObj2);
     net->runUntil(net->now() + Seconds(10));  // run until we've sent a heartbeat request
     const NetworkInterfaceMock::NetworkOperationIterator noi2 = net->getNextReadyRequest();
     net->scheduleResponse(noi2, net->now(), makeResponseStatus(respObj2.obj()));
@@ -621,7 +621,7 @@ TEST_F(ReplCoordTest, NodeDoesNotAcceptHeartbeatReconfigWhileInTheMidstOfReconfi
     hbResp.setState(MemberState::RS_SECONDARY);
     BSONObjBuilder respObj2;
     respObj2 << "ok" << 1;
-    hbResp.addToBSON(&respObj2, false);
+    hbResp.addToBSON(&respObj2);
     net->scheduleResponse(noi, net->now(), makeResponseStatus(respObj2.obj()));
 
     logger::globalLogDomain()->setMinimumLoggedSeverity(logger::LogSeverity::Debug(1));
diff --git a/src/mongo/db/repl/replication_coordinator_impl_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
index 7af5b422e8a..49809d3dafb 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
@@ -382,10 +382,9 @@ TEST_F(ReplCoordTest, InitiateSucceedsWhenQuorumCheckPasses) {
     ASSERT_BSONOBJ_EQ(hbArgs.toBSON(), noi->getRequest().cmdObj);
     ReplSetHeartbeatResponse hbResp;
     hbResp.setConfigVersion(0);
-    getNet()->scheduleResponse(
-        noi,
-        startDate + Milliseconds(10),
-        RemoteCommandResponse(hbResp.toBSON(false), BSONObj(), Milliseconds(8)));
+    getNet()->scheduleResponse(noi,
+                               startDate + Milliseconds(10),
+                               RemoteCommandResponse(hbResp.toBSON(), BSONObj(), Milliseconds(8)));
     getNet()->runUntil(startDate + Milliseconds(10));
     getNet()->exitNetwork();
     ASSERT_EQUALS(startDate + Milliseconds(10), getNet()->now());
@@ -1354,7 +1353,7 @@ protected:
             hbResp.setDurableOpTime(desiredOpTime);
             BSONObjBuilder respObj;
             respObj << "ok" << 1;
-            hbResp.addToBSON(&respObj, false);
+            hbResp.addToBSON(&respObj);
             getNet()->scheduleResponse(noi, getNet()->now(), makeResponseStatus(respObj.obj()));
         }
         while (getNet()->hasReadyRequests()) {
@@ -1863,7 +1862,7 @@ protected:
             hbResp.setAppliedOpTime(optimeResponse);
             BSONObjBuilder respObj;
             respObj << "ok" << 1;
-            hbResp.addToBSON(&respObj, false);
+            hbResp.addToBSON(&respObj);
             getNet()->scheduleResponse(noi, getNet()->now(), makeResponseStatus(respObj.obj()));
             hbNum += 1;
         }
@@ -2166,7 +2165,7 @@ TEST_F(StepDownTest,
         hbResp.setConfigVersion(hbArgs.getConfigVersion());
         BSONObjBuilder respObj;
         respObj << "ok" << 1;
-        hbResp.addToBSON(&respObj, false);
+        hbResp.addToBSON(&respObj);
         getNet()->scheduleResponse(noi, getNet()->now(), makeResponseStatus(respObj.obj()));
     }
     while (getNet()->hasReadyRequests()) {
@@ -4488,7 +4487,7 @@ TEST_F(ReplCoordTest,
     hbResp.setConfigVersion(config.getConfigVersion());
     hbResp.setSetName(config.getReplSetName());
     hbResp.setState(MemberState::RS_SECONDARY);
-    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true), metadataObj));
+    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(), metadataObj));
     net->runReadyNetworkOperations();
     net->exitNetwork();
 
@@ -4614,7 +4613,7 @@ TEST_F(ReplCoordTest, TermAndLastCommittedOpTimeUpdatedFromHeartbeatWhenArbiter)
     hbResp.setConfigVersion(config.getConfigVersion());
     hbResp.setSetName(config.getReplSetName());
     hbResp.setState(MemberState::RS_SECONDARY);
-    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true), metadataObj));
+    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(), metadataObj));
     net->runReadyNetworkOperations();
     net->exitNetwork();
 
@@ -4788,7 +4787,7 @@ TEST_F(ReplCoordTest,
     hbResp.setConfigVersion(3);
     hbResp.setSetName("mySet");
     hbResp.setState(MemberState::RS_SECONDARY);
-    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true)));
+    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON()));
     net->runReadyNetworkOperations();
     net->exitNetwork();
 
@@ -4844,7 +4843,7 @@ TEST_F(ReplCoordTest,
     // Heartbeat response is scheduled with a delay so that we can be sure that
     // the election was rescheduled due to the heartbeat response.
     auto heartbeatWhen = net->now() + Seconds(1);
-    net->scheduleResponse(noi, heartbeatWhen, makeResponseStatus(hbResp.toBSON(true)));
+    net->scheduleResponse(noi, heartbeatWhen, makeResponseStatus(hbResp.toBSON()));
     net->runUntil(heartbeatWhen);
     ASSERT_EQUALS(heartbeatWhen, net->now());
     net->runReadyNetworkOperations();
@@ -4898,7 +4897,7 @@ TEST_F(ReplCoordTest,
     // Heartbeat response is scheduled with a delay so that we can be sure that
     // the election was rescheduled due to the heartbeat response.
     auto heartbeatWhen = net->now() + Seconds(1);
-    net->scheduleResponse(noi, heartbeatWhen, makeResponseStatus(hbResp.toBSON(true)));
+    net->scheduleResponse(noi, heartbeatWhen, makeResponseStatus(hbResp.toBSON()));
     net->runUntil(heartbeatWhen);
     ASSERT_EQUALS(heartbeatWhen, net->now());
     net->runReadyNetworkOperations();
@@ -4949,7 +4948,7 @@ TEST_F(ReplCoordTest,
     // Heartbeat response is scheduled with a delay so that we can be sure that
     // the election was rescheduled due to the heartbeat response.
     auto heartbeatWhen = net->now() + Seconds(1);
-    net->scheduleResponse(noi, heartbeatWhen, makeResponseStatus(hbResp.toBSON(true)));
+    net->scheduleResponse(noi, heartbeatWhen, makeResponseStatus(hbResp.toBSON()));
     net->runUntil(heartbeatWhen);
     ASSERT_EQUALS(heartbeatWhen, net->now());
     net->runReadyNetworkOperations();
diff --git a/src/mongo/db/repl/replication_coordinator_mock.cpp b/src/mongo/db/repl/replication_coordinator_mock.cpp
index a4c1c5d6700..6e4f2e339af 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_mock.cpp
@@ -408,10 +408,6 @@ Status ReplicationCoordinatorMock::processHeartbeatV1(const ReplSetHeartbeatArgs
     return Status::OK();
 }
 
-bool ReplicationCoordinatorMock::isV1ElectionProtocol() const {
-    return true;
-}
-
 bool ReplicationCoordinatorMock::getWriteConcernMajorityShouldJournal() {
     return true;
 }
diff --git a/src/mongo/db/repl/replication_coordinator_mock.h b/src/mongo/db/repl/replication_coordinator_mock.h
index 7b85930f7d5..a784b5093e1 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_mock.h
@@ -224,8 +224,6 @@ public:
     virtual Status processHeartbeatV1(const ReplSetHeartbeatArgsV1& args,
                                       ReplSetHeartbeatResponse* response);
 
-    virtual bool isV1ElectionProtocol() const override;
-
     virtual bool getWriteConcernMajorityShouldJournal();
 
     virtual void summarizeAsHtml(ReplSetHtmlSummary* output);
diff --git a/src/mongo/db/repl/replication_coordinator_test_fixture.cpp b/src/mongo/db/repl/replication_coordinator_test_fixture.cpp
index 23347464610..7fb82bf5f57 100644
--- a/src/mongo/db/repl/replication_coordinator_test_fixture.cpp
+++ b/src/mongo/db/repl/replication_coordinator_test_fixture.cpp
@@ -240,7 +240,7 @@ void ReplCoordTest::simulateEnoughHeartbeatsForAllNodesUp() {
             hbResp.setConfigVersion(rsConfig.getConfigVersion());
             hbResp.setAppliedOpTime(OpTime(Timestamp(100, 2), 0));
             BSONObjBuilder respObj;
-            net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true)));
+            net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON()));
         } else {
             error() << "Black holing unexpected request to " << request.target << ": "
                     << request.cmdObj;
@@ -343,7 +343,7 @@ void ReplCoordTest::simulateSuccessfulV1ElectionWithoutExitingDrainMode(Date_t e
             hbResp.setAppliedOpTime(opTime);
             hbResp.setDurableOpTime(opTime);
             hbResp.setConfigVersion(rsConfig.getConfigVersion());
-            net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true)));
+            net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON()));
         } else if (request.cmdObj.firstElement().fieldNameStringData() == "replSetRequestVotes") {
             net->scheduleResponse(noi,
                                   net->now(),
@@ -436,7 +436,7 @@ bool ReplCoordTest::consumeHeartbeatV1(const NetworkInterfaceMock::NetworkOperat
     hbResp.setConfigVersion(rsConfig.getConfigVersion());
     hbResp.setAppliedOpTime(lastApplied);
     BSONObjBuilder respObj;
-    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON(true)));
+    net->scheduleResponse(noi, net->now(), makeResponseStatus(hbResp.toBSON()));
     return true;
 }
 
diff --git a/src/mongo/db/repl/rollback_impl.cpp b/src/mongo/db/repl/rollback_impl.cpp
index 1d0f78b76e7..c1557c9d522 100644
--- a/src/mongo/db/repl/rollback_impl.cpp
+++ b/src/mongo/db/repl/rollback_impl.cpp
@@ -660,10 +660,8 @@ StatusWith<RollBackLocalOperations::RollbackCommonPoint> RollbackImpl::_findComm
     log() << "Rollback common point is " << commonPointOpTime;
 
     // Rollback common point should be >= the replication commit point.
-    invariant(!_replicationCoordinator->isV1ElectionProtocol() ||
-              commonPointOpTime.getTimestamp() >= lastCommittedOpTime.getTimestamp());
-    invariant(!_replicationCoordinator->isV1ElectionProtocol() ||
-              commonPointOpTime >= lastCommittedOpTime);
+    invariant(commonPointOpTime.getTimestamp() >= lastCommittedOpTime.getTimestamp());
+    invariant(commonPointOpTime >= lastCommittedOpTime);
 
     // Rollback common point should be >= the committed snapshot optime.
     invariant(commonPointOpTime.getTimestamp() >= committedSnapshot.getTimestamp());
diff --git a/src/mongo/db/repl/rs_rollback.cpp b/src/mongo/db/repl/rs_rollback.cpp
index 8a6c6a0ae62..0ce3a34d3ea 100644
--- a/src/mongo/db/repl/rs_rollback.cpp
+++ b/src/mongo/db/repl/rs_rollback.cpp
@@ -934,9 +934,8 @@ Status _syncRollback(OperationContext* opCtx,
     log() << "Rollback common point is " << commonPoint;
 
     // Rollback common point should be >= the replication commit point.
-    invariant(!replCoord->isV1ElectionProtocol() ||
-              commonPoint.getTimestamp() >= lastCommittedOpTime.getTimestamp());
-    invariant(!replCoord->isV1ElectionProtocol() || commonPoint >= lastCommittedOpTime);
+    invariant(commonPoint.getTimestamp() >= lastCommittedOpTime.getTimestamp());
+    invariant(commonPoint >= lastCommittedOpTime);
 
     // Rollback common point should be >= the committed snapshot optime.
     invariant(commonPoint.getTimestamp() >= committedSnapshot.getTimestamp());
diff --git a/src/mongo/embedded/replication_coordinator_embedded.cpp b/src/mongo/embedded/replication_coordinator_embedded.cpp
index 6fd8bf5a086..381a34574db 100644
--- a/src/mongo/embedded/replication_coordinator_embedded.cpp
+++ b/src/mongo/embedded/replication_coordinator_embedded.cpp
@@ -364,10 +364,6 @@ void ReplicationCoordinatorEmbedded::prepareReplMetadata(const BSONObj&,
     UASSERT_NOT_IMPLEMENTED;
 }
 
-bool ReplicationCoordinatorEmbedded::isV1ElectionProtocol() const {
-    UASSERT_NOT_IMPLEMENTED;
-}
-
 bool ReplicationCoordinatorEmbedded::getWriteConcernMajorityShouldJournal() {
     UASSERT_NOT_IMPLEMENTED;
 }
diff --git a/src/mongo/embedded/replication_coordinator_embedded.h b/src/mongo/embedded/replication_coordinator_embedded.h
index 2136186f544..24eda7e109f 100644
--- a/src/mongo/embedded/replication_coordinator_embedded.h
+++ b/src/mongo/embedded/replication_coordinator_embedded.h
@@ -196,8 +196,6 @@ public:
     Status processHeartbeatV1(const repl::ReplSetHeartbeatArgsV1&,
                               repl::ReplSetHeartbeatResponse*) override;
 
-    bool isV1ElectionProtocol() const override;
-
     bool getWriteConcernMajorityShouldJournal() override;
 
     void summarizeAsHtml(repl::ReplSetHtmlSummary*) override;