diff --git a/dbms/src/Storages/MergeTree/DataPartsExchange.cpp b/dbms/src/Storages/MergeTree/DataPartsExchange.cpp
index f648b7f3fb7ddadc3784e840dcbe175714d20a2b..11fa64739d360c551ec4ab4199974e379bd2c762 100644
--- a/dbms/src/Storages/MergeTree/DataPartsExchange.cpp
+++ b/dbms/src/Storages/MergeTree/DataPartsExchange.cpp
@@ -25,7 +25,6 @@ namespace ErrorCodes
     extern const int BAD_SIZE_OF_FILE_IN_DATA_PART;
     extern const int CANNOT_WRITE_TO_OSTREAM;
     extern const int CHECKSUM_DOESNT_MATCH;
-    extern const int UNKNOWN_PROTOCOL;
     extern const int INSECURE_PATH;
 }
 
@@ -34,10 +33,8 @@ namespace DataPartsExchange
 
 namespace
 {
-
-static constexpr auto REPLICATION_PROTOCOL_VERSION_WITHOUT_PARTS_SIZE = "0";
-static constexpr auto REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE = "1";
-static constexpr auto REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS = "2";
+static constexpr auto REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE = 1;
+static constexpr auto REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS = 2;
 
 
 std::string getEndpointId(const std::string & node_id)
@@ -54,15 +51,10 @@ std::string Service::getId(const std::string & node_id) const
 
 void Service::processQuery(const Poco::Net::HTMLForm & params, ReadBuffer & /*body*/, WriteBuffer & out, Poco::Net::HTTPServerResponse & response)
 {
-    String client_protocol_version = params.get("client_protocol_version", REPLICATION_PROTOCOL_VERSION_WITHOUT_PARTS_SIZE);
+    int client_protocol_version = parse<int>(params.get("client_protocol_version", "0"));
 
     String part_name = params.get("part");
 
-    if (client_protocol_version != REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS
-        && client_protocol_version != REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE
-        && client_protocol_version != REPLICATION_PROTOCOL_VERSION_WITHOUT_PARTS_SIZE)
-        throw Exception("Unsupported fetch protocol version", ErrorCodes::UNKNOWN_PROTOCOL);
-
     const auto data_settings = data.getSettings();
 
     /// Validation of the input that may come from malicious replica.
@@ -79,7 +71,9 @@ void Service::processQuery(const Poco::Net::HTMLForm & params, ReadBuffer & /*bo
         response.setChunkedTransferEncoding(false);
         return;
     }
-    response.addCookie({"server_protocol_version", REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS});
+
+    /// We pretend to work as older server version, to be sure that client will correctly process our version
+    response.addCookie({"server_protocol_version", toString(std::min(client_protocol_version, REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS))});
 
     ++total_sends;
     SCOPE_EXIT({--total_sends;});
@@ -107,10 +101,10 @@ void Service::processQuery(const Poco::Net::HTMLForm & params, ReadBuffer & /*bo
 
         MergeTreeData::DataPart::Checksums data_checksums;
 
-        if (client_protocol_version == REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE || client_protocol_version == REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)
+        if (client_protocol_version >= REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE)
             writeBinary(checksums.getTotalSizeOnDisk(), out);
 
-        if (client_protocol_version == REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)
+        if (client_protocol_version >= REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)
         {
             WriteBufferFromOwnString ttl_infos_buffer;
             part->ttl_infos.write(ttl_infos_buffer);
@@ -202,7 +196,7 @@ MergeTreeData::MutableDataPartPtr Fetcher::fetchPart(
     {
         {"endpoint",                getEndpointId(replica_path)},
         {"part",                    part_name},
-        {"client_protocol_version", REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS},
+        {"client_protocol_version", toString(REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)},
         {"compress",                "false"}
     });
 
@@ -224,15 +218,14 @@ MergeTreeData::MutableDataPartPtr Fetcher::fetchPart(
         data_settings->replicated_max_parallel_fetches_for_host
     };
 
-    auto server_protocol_version = in.getResponseCookie("server_protocol_version", REPLICATION_PROTOCOL_VERSION_WITHOUT_PARTS_SIZE);
-
+    int server_protocol_version = parse<int>(in.getResponseCookie("server_protocol_version", "0"));
 
     ReservationPtr reservation;
-    if (server_protocol_version == REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE || server_protocol_version == REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)
+    if (server_protocol_version >= REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE)
     {
         size_t sum_files_size;
         readBinary(sum_files_size, in);
-        if (server_protocol_version == REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)
+        if (server_protocol_version >= REPLICATION_PROTOCOL_VERSION_WITH_PARTS_SIZE_AND_TTL_INFOS)
         {
             IMergeTreeDataPart::TTLInfos ttl_infos;
             String ttl_infos_string;
diff --git a/dbms/tests/integration/test_backward_compatability/__init__.py b/dbms/tests/integration/test_backward_compatability/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/dbms/tests/integration/test_backward_compatability/test.py b/dbms/tests/integration/test_backward_compatability/test.py
new file mode 100644
index 0000000000000000000000000000000000000000..914153342f890a39fede8631e9bdf36f083f37eb
--- /dev/null
+++ b/dbms/tests/integration/test_backward_compatability/test.py
@@ -0,0 +1,31 @@
+import pytest
+
+import helpers.client as client
+from helpers.cluster import ClickHouseCluster
+
+cluster = ClickHouseCluster(__file__)
+node1 = cluster.add_instance('node1', with_zookeeper=True, image='yandex/clickhouse-server:19.17.8.54', stay_alive=True, with_installed_binary=True)
+node2 = cluster.add_instance('node2', with_zookeeper=True)
+
+@pytest.fixture(scope="module")
+def start_cluster():
+    try:
+        cluster.start()
+        for i, node in enumerate([node1, node2]):
+            node.query(
+            '''CREATE TABLE t(date Date, id UInt32)
+            ENGINE = ReplicatedMergeTree('/clickhouse/tables/test/t', '{}')
+            PARTITION BY toYYYYMM(date)
+            ORDER BY id'''.format(i))
+
+        yield cluster
+
+    finally:
+        cluster.shutdown()
+
+
+def test_backward_compatability(start_cluster):
+    node2.query("INSERT INTO t VALUES (today(), 1)")
+    node1.query("SYSTEM SYNC REPLICA t", timeout=10)
+
+    assert node1.query("SELECT count() FROM t") == "1\n"