diff --git a/README.md b/README.md
index 389b638..030fc5f 100644
--- a/README.md
+++ b/README.md
@@ -53,8 +53,10 @@ This microservice allows sending and receiving messages via FIX protocol
 + *logoutOnIncorrectServerSequence* - whether to logout session when server send message with sequence number less than expected. If `false` then internal conn sequence will be reset to sequence number from server message.
 + *connectionTimeoutOnSend* - timeout in milliseconds for sending message from queue thread
   (please read about [acknowledgment timeout](https://www.rabbitmq.com/consumers.html#acknowledgement-timeout) to understand the problem).
-  _Default, 30000 mls._
+  _Default, 30000 mls._ Each failed sending attempt decreases the timeout in half (but not less than _minConnectionTimeoutOnSend_).
+  The timeout is reset to the original value after a successful sending attempt.
   If connection is not established within the specified timeout an error will be reported.
++ *minConnectionTimeoutOnSend* - minimum value for the sending message timeout in milliseconds. _Default value is 1000 mls._
 
 ### Security settings
 
@@ -334,6 +336,17 @@ spec:
 
 # Changelog
 
+## 1.5.1
+
+* Property `th2.operation_timestamp` is added to metadata to each message
+* Use mutable map for metadata when sending a messages from the handler
+  * Fix error when new property with operation timestamp added to the immutable map
+
+## 1.5.0
+
+* `minConnectionTimeoutOnSend` parameter is added.
+* Sending timeout now decreases in half on each failed attempt (but not less than `minConnectionTimeoutOnSend`).
+
 ## 1.4.2
 * Ungraceful session disconnect support.
 * Removed NPE when session is reset by schedule.
diff --git a/build.gradle b/build.gradle
index bbaceca..8063861 100644
--- a/build.gradle
+++ b/build.gradle
@@ -55,7 +55,7 @@ dependencies {
     implementation 'com.exactpro.th2:netty-bytebuf-utils:0.0.1'
     implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.15.2'
 
-    implementation 'com.exactpro.th2:conn-dirty-tcp-core:3.2.1-TH2-5001+'
+    implementation 'com.exactpro.th2:conn-dirty-tcp-core:3.3.0-TH2-5001+'
     implementation 'com.exactpro.th2:grpc-lw-data-provider:2.2.0-dev'
 
     implementation 'org.slf4j:slf4j-api'
diff --git a/src/main/java/com/exactpro/th2/FixHandler.java b/src/main/java/com/exactpro/th2/FixHandler.java
index fc8e8d8..79c82e3 100644
--- a/src/main/java/com/exactpro/th2/FixHandler.java
+++ b/src/main/java/com/exactpro/th2/FixHandler.java
@@ -46,6 +46,7 @@
 import com.exactpro.th2.conn.dirty.fix.brokenconn.strategy.StrategyScheduler;
 import com.exactpro.th2.conn.dirty.fix.brokenconn.strategy.StrategyState;
 import com.exactpro.th2.conn.dirty.fix.brokenconn.strategy.api.CleanupHandler;
+import com.exactpro.th2.conn.dirty.tcp.core.SendingTimeoutHandler;
 import com.exactpro.th2.conn.dirty.tcp.core.api.IChannel;
 import com.exactpro.th2.conn.dirty.tcp.core.api.IChannel.SendMode;
 import com.exactpro.th2.conn.dirty.tcp.core.api.IHandler;
@@ -217,6 +218,8 @@ public class FixHandler implements AutoCloseable, IHandler {
 
     private final AtomicReference<Future<?>> heartbeatTimer = new AtomicReference<>(CompletableFuture.completedFuture(null));
     private final AtomicReference<Future<?>> testRequestTimer = new AtomicReference<>(CompletableFuture.completedFuture(null));
+
+    private final SendingTimeoutHandler sendingTimeoutHandler;
     private Future<?> reconnectRequestTimer = CompletableFuture.completedFuture(null);
     private volatile IChannel channel;
     protected FixHandlerSettings settings;
@@ -302,6 +305,12 @@ public FixHandler(IHandlerContext context) {
             throw new IllegalStateException("`newPassword` contains password that was already used in the past.");
         }
 
+        this.sendingTimeoutHandler = SendingTimeoutHandler.create(
+            settings.getMinConnectionTimeoutOnSend(),
+            settings.getConnectionTimeoutOnSend(),
+            context::send
+        );
+
         if (settings.getBrokenConnConfiguration() == null) {
             scheduler = new StrategyScheduler(SchedulerType.CONSECUTIVE, Collections.emptyList());
             return;
@@ -349,21 +358,26 @@ public CompletableFuture<MessageID> send(@NotNull ByteBuf body, @NotNull Map<Str
             try {
                 disconnect(!isUngracefulDisconnect);
                 enabled.set(false);
-                channel.open().get(settings.getConnectionTimeoutOnSend(), TimeUnit.MILLISECONDS);
+                sendingTimeoutHandler.getWithTimeout(channel.open());
             } catch (Exception e) {
                 context.send(CommonUtil.toErrorEvent(String.format("Error while ending session %s by user logout. Is graceful disconnect: %b", channel.getSessionAlias(), !isUngracefulDisconnect), e));
             }
             return CompletableFuture.completedFuture(null);
         }
 
-        long deadline = System.currentTimeMillis() + settings.getConnectionTimeoutOnSend();
+        // TODO: probably, this should be moved to the core part
+        // But those changes will break API
+        // So, let's keep it here for now
+        long deadline = sendingTimeoutHandler.getDeadline();
+        long currentTimeout = sendingTimeoutHandler.getCurrentTimeout();
+
         if (!channel.isOpen()) {
             try {
-                channel.open().get(settings.getConnectionTimeoutOnSend(), TimeUnit.MILLISECONDS);
+                sendingTimeoutHandler.getWithTimeout(channel.open());
             } catch (TimeoutException e) {
                 ExceptionUtils.rethrow(new TimeoutException(
                         String.format("could not open connection before timeout %d mls elapsed",
-                                settings.getConnectionTimeoutOnSend())));
+                                currentTimeout)));
             } catch (Exception e) {
                 ExceptionUtils.rethrow(e);
             }
@@ -724,10 +738,14 @@ private void reset() {
         if(!channel.isOpen()) channel.open();
     }
 
-    public void sendResendRequest(int beginSeqNo, int endSeqNo) { //do private
+    public void sendResendRequest(int beginSeqNo, int endSeqNo) {
+        sendResendRequest(beginSeqNo, endSeqNo, false);
+    }
+
+    public void sendResendRequest(int beginSeqNo, int endSeqNo, boolean isPossDup) { //do private
         LOGGER.info("Sending resend request: {} - {}", beginSeqNo, endSeqNo);
         StringBuilder resendRequest = new StringBuilder();
-        setHeader(resendRequest, MSG_TYPE_RESEND_REQUEST, msgSeqNum.incrementAndGet(), null);
+        setHeader(resendRequest, MSG_TYPE_RESEND_REQUEST, msgSeqNum.incrementAndGet(), null, isPossDup);
         resendRequest.append(BEGIN_SEQ_NO).append(beginSeqNo);
         resendRequest.append(END_SEQ_NO).append(endSeqNo);
         setChecksumAndBodyLength(resendRequest);
@@ -747,8 +765,6 @@ void sendResendRequest(int beginSeqNo) { //do private
             channel.send(Unpooled.wrappedBuffer(resendRequest.toString().getBytes(StandardCharsets.UTF_8)), new HashMap<String, String>(), null, SendMode.HANDLE_AND_MANGLE)
                 .thenAcceptAsync(x -> strategy.getState().addMessageID(x), executorService);
             resetHeartbeatTask();
-        } else {
-            sendLogon();
         }
     }
 
@@ -1030,15 +1046,23 @@ public void onOpen(@NotNull IChannel channel) {
         sendLogon();
     }
 
+    public void sendHeartbeatWithPossDup(boolean isPossDup) {
+        sendHeartbeatWithTestRequest(null, isPossDup);
+    }
+
+    private void sendHeartbeatWithTestRequest(String testRequestID) {
+        sendHeartbeatWithTestRequest(testRequestID, false);
+    }
+
     public void sendHeartbeat() {
-        sendHeartbeatWithTestRequest(null);
+        sendHeartbeatWithTestRequest(null, false);
     }
 
-    private void sendHeartbeatWithTestRequest(String testRequestId) {
+    private void sendHeartbeatWithTestRequest(String testRequestId, boolean possDup) {
         StringBuilder heartbeat = new StringBuilder();
         int seqNum = msgSeqNum.incrementAndGet();
 
-        setHeader(heartbeat, MSG_TYPE_HEARTBEAT, seqNum, null);
+        setHeader(heartbeat, MSG_TYPE_HEARTBEAT, seqNum, null, possDup);
 
         if(testRequestId != null) {
             heartbeat.append(TEST_REQ_ID).append(testRequestId);
@@ -1057,8 +1081,12 @@ private void sendHeartbeatWithTestRequest(String testRequestId) {
     }
 
     public void sendTestRequest() { //do private
+        sendTestRequestWithPossDup(false);
+    }
+
+    public void sendTestRequestWithPossDup(boolean isPossDup) { //do private
         StringBuilder testRequest = new StringBuilder();
-        setHeader(testRequest, MSG_TYPE_TEST_REQUEST, msgSeqNum.incrementAndGet(), null);
+        setHeader(testRequest, MSG_TYPE_TEST_REQUEST, msgSeqNum.incrementAndGet(), null, isPossDup);
         testRequest.append(TEST_REQ_ID).append(testReqID.incrementAndGet());
         setChecksumAndBodyLength(testRequest);
         if (enabled.get()) {
@@ -1115,14 +1143,22 @@ public void sendLogon() {
             .thenAcceptAsync(x -> strategy.getState().addMessageID(x), executorService);
     }
 
-    private void sendLogout() {
-        sendLogout(null);
+    private void sendLogout(boolean isPossDup) {
+        sendLogout(null, isPossDup);
     }
 
     private void sendLogout(String text) {
+        sendLogout(text, false);
+    }
+
+    private void sendLogout() {
+        sendLogout(null, false);
+    }
+
+    private void sendLogout(String text, boolean isPossDup) {
         if (enabled.get()) {
             StringBuilder logout = new StringBuilder();
-            setHeader(logout, MSG_TYPE_LOGOUT, msgSeqNum.incrementAndGet(), null);
+            setHeader(logout, MSG_TYPE_LOGOUT, msgSeqNum.incrementAndGet(), null, isPossDup);
             if(text != null) {
                logout.append(TEXT).append(text);
             }
@@ -1582,6 +1618,22 @@ private void runLogonAfterLogonStrategy(RuleConfiguration configuration) {
         ruleEndEvent(configuration.getRuleType(), start, strategy.getState().getMessageIDs());
     }
 
+    private void runPossDupSessionMessages(RuleConfiguration configuration) {
+        Instant start = Instant.now();
+        strategy.resetStrategyAndState(configuration);
+        ruleStartEvent(configuration.getRuleType(), strategy.getStartTime());
+        if(!enabled.get()) {
+            ruleErrorEvent(strategy.getType(), String.format("Session %s isn't logged in.", channel.getSessionAlias()), null);
+            return;
+        }
+
+        sendResendRequest(serverMsgSeqNum.get() - 2, serverMsgSeqNum.get(), true);
+        sendHeartbeatWithPossDup(true);
+        sendTestRequestWithPossDup(true);
+        sendLogout(true);
+        ruleEndEvent(configuration.getRuleType(), start, strategy.getState().getMessageIDs());
+    }
+
     private void setupDisconnectStrategy(RuleConfiguration configuration) {
         strategy.resetStrategyAndState(configuration);
         strategy.updateSendStrategy(x -> {x.setSendPreprocessor(this::blockSend); return Unit.INSTANCE; });
@@ -1975,7 +2027,9 @@ private Consumer<RuleConfiguration> getSetupFunction(RuleConfiguration config) {
             case IGNORE_INCOMING_MESSAGES: return this::setupIgnoreIncomingMessagesStrategy;
             case DISCONNECT_WITH_RECONNECT: return this::setupDisconnectStrategy;
             case FAKE_RETRANSMISSION: return this::setupFakeRetransmissionStrategy;
+            case INVALID_CHECKSUM: return this::setupTransformMessageStrategy;
             case LOGON_AFTER_LOGON: return this::runLogonAfterLogonStrategy;
+            case POSS_DUP_SESSION_MESSAGES: return this::runPossDupSessionMessages;
             case DEFAULT: return configuration -> strategy.cleanupStrategy();
             default: throw new IllegalStateException(String.format("Unknown strategy type %s.", config.getRuleType()));
         }
@@ -2130,6 +2184,10 @@ private void waitLogoutResponse() {
     }
 
     private void setHeader(StringBuilder stringBuilder, String msgType, Integer seqNum, String time) {
+        setHeader(stringBuilder, msgType, seqNum, time, false);
+    }
+
+    private void setHeader(StringBuilder stringBuilder, String msgType, Integer seqNum, String time, boolean isPossDup) {
         stringBuilder.append(BEGIN_STRING_TAG).append("=").append(settings.getBeginString());
         stringBuilder.append(MSG_TYPE).append(msgType);
         stringBuilder.append(MSG_SEQ_NUM).append(seqNum);
@@ -2142,6 +2200,9 @@ private void setHeader(StringBuilder stringBuilder, String msgType, Integer seqN
         } else {
             stringBuilder.append(getTime());
         }
+        if(isPossDup) {
+            stringBuilder.append(POSS_DUP).append(IS_POSS_DUP);
+        }
     }
 
     private void setChecksumAndBodyLength(StringBuilder stringBuilder) {
diff --git a/src/main/java/com/exactpro/th2/FixHandlerSettings.java b/src/main/java/com/exactpro/th2/FixHandlerSettings.java
index 76ea112..b3d6c0a 100644
--- a/src/main/java/com/exactpro/th2/FixHandlerSettings.java
+++ b/src/main/java/com/exactpro/th2/FixHandlerSettings.java
@@ -80,6 +80,8 @@ public class FixHandlerSettings implements IHandlerSettings {
      */
     private long connectionTimeoutOnSend = DEFAULT_CONNECTION_TIMEOUT_ON_SEND;
 
+    private long minConnectionTimeoutOnSend = 1_000;
+
     @JsonDeserialize(using = DateTimeFormatterDeserializer.class)
     private DateTimeFormatter sendingDateTimeFormat = DateTimeFormatter.ofPattern("yyyyMMdd-HH:mm:ss.SSSSSSSSS");
 
@@ -338,4 +340,12 @@ public long getConnectionTimeoutOnSend() {
     public void setConnectionTimeoutOnSend(long connectionTimeoutOnSend) {
         this.connectionTimeoutOnSend = connectionTimeoutOnSend;
     }
+
+    public long getMinConnectionTimeoutOnSend() {
+        return minConnectionTimeoutOnSend;
+    }
+
+    public void setMinConnectionTimeoutOnSend(long minConnectionTimeoutOnSend) {
+        this.minConnectionTimeoutOnSend = minConnectionTimeoutOnSend;
+    }
 }
diff --git a/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/configuration/RuleConfiguration.kt b/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/configuration/RuleConfiguration.kt
index adfc67f..633a605 100644
--- a/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/configuration/RuleConfiguration.kt
+++ b/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/configuration/RuleConfiguration.kt
@@ -54,6 +54,9 @@ data class RuleConfiguration(
             RuleType.TRANSFORM_MESSAGE_STRATEGY -> {
                 require(transformMessageConfiguration != null) { "`transformMessageConfiguration` is required for $ruleType"}
             }
+            RuleType.INVALID_CHECKSUM -> {
+                require(transformMessageConfiguration != null) { "`transformMessageConfiguration` is required for $ruleType" }
+            }
             RuleType.BI_DIRECTIONAL_RESEND_REQUEST -> {
                 require(missIncomingMessagesConfiguration != null) { "`blockIncomingMessagesConfiguration` is required for $ruleType" }
                 require(missOutgoingMessagesConfiguration != null) { "`blockOutgoingMessagesConfiguration` is required for $ruleType" }
@@ -79,6 +82,7 @@ data class RuleConfiguration(
             RuleType.DEFAULT -> {}
             RuleType.FAKE_RETRANSMISSION -> {}
             RuleType.LOGON_AFTER_LOGON -> {}
+            RuleType.POSS_DUP_SESSION_MESSAGES -> {}
         }
     }
 
diff --git a/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/strategy/RuleType.kt b/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/strategy/RuleType.kt
index 1ea5311..5f18782 100644
--- a/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/strategy/RuleType.kt
+++ b/src/main/kotlin/com/exactpro/th2/conn/dirty/fix/brokenconn/strategy/RuleType.kt
@@ -32,5 +32,7 @@ enum class RuleType {
     SPLIT_SEND,
     LOGON_AFTER_LOGON,
     FAKE_RETRANSMISSION,
+    INVALID_CHECKSUM,
+    POSS_DUP_SESSION_MESSAGES,
     DEFAULT
 }
\ No newline at end of file
diff --git a/src/test/java/com/exactpro/th2/FixHandlerSendTimeoutTest.java b/src/test/java/com/exactpro/th2/FixHandlerSendTimeoutTest.java
index 4353258..5e81642 100644
--- a/src/test/java/com/exactpro/th2/FixHandlerSendTimeoutTest.java
+++ b/src/test/java/com/exactpro/th2/FixHandlerSendTimeoutTest.java
@@ -59,6 +59,7 @@ void sendTimeoutOnConnectionOpen() {
         settings.setPort(42);
         settings.setHost("localhost");
         settings.setConnectionTimeoutOnSend(300); // 300 millis
+        settings.setMinConnectionTimeoutOnSend(100);
         Mockito.when(contextMock.getSettings())
                 .thenReturn(settings);
         var fixHandler = new FixHandler(contextMock);
@@ -100,6 +101,7 @@ void sendTimeoutOnSessionEnabled() {
         settings.setPort(42);
         settings.setHost("localhost");
         settings.setConnectionTimeoutOnSend(300); // 300 millis
+        settings.setMinConnectionTimeoutOnSend(100);
         LocalTime currentTime = LocalTime.now(ZoneOffset.UTC);
         int deltaMinutes = currentTime.isAfter(LocalTime.NOON)
                 ? -1