diff --git a/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClient.java b/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClient.java
index 4459cac7ce..065c7a74f7 100644
--- a/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClient.java
+++ b/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClient.java
@@ -58,7 +58,6 @@
 
 public class DavClient {
     public static final int MAX_CALENDAR_OBJECT_UPDATE_RETRIES = 5;
-    public static final Duration MIN_CALENDAR_OBJECT_UPDATE_RETRY_BACKOFF = Duration.ofMillis(100);
 
     private static final Logger LOGGER = LoggerFactory.getLogger(DavClient.class);
     private static final Duration DEFAULT_RESPONSE_TIMEOUT = Duration.ofSeconds(10);
@@ -67,10 +66,14 @@ public class DavClient {
     private static final String ACCEPT_VCARD_JSON = "application/vcard+json";
     private static final String ACCEPT_XML = "application/xml";
     private static final String CONTENT_TYPE_VCARD = "application/vcard";
-    private static final boolean SHOULD_RETRY_CALENDAR_OBJECT_UPDATE = true;
 
     private final HttpClient client;
     private final DavConfiguration config;
+    public final Duration calendarObjectUpdateRetryBackoff =
+        Optional.ofNullable(System.getProperty("MIN_CALENDAR_OBJECT_UPDATE_RETRY_BACKOFF_IN_MILLS"))
+            .map(Long::parseLong)
+            .map(Duration::ofMillis)
+            .orElse(Duration.ofMillis(100));
 
     public DavClient(DavConfiguration config) {
         this.config = config;
@@ -157,8 +160,8 @@ public Mono<Void> updateCalendarObject(String username, URI calendarObjectUri, F
             .map(calendarObjectUpdater)
             .flatMap(updatedCalendarObject -> doUpdateCalendarObject(username, updatedCalendarObject))
             .retryWhen(
-                Retry.backoff(MAX_CALENDAR_OBJECT_UPDATE_RETRIES, MIN_CALENDAR_OBJECT_UPDATE_RETRY_BACKOFF)
-                .filter(e -> e instanceof DavClientException && ((DavClientException) e).shouldRetry())
+                Retry.backoff(MAX_CALENDAR_OBJECT_UPDATE_RETRIES, calendarObjectUpdateRetryBackoff)
+                .filter(RetriableDavClientException.class::isInstance)
                 .onRetryExhaustedThrow((retryBackoffSpec, retrySignal) ->
                     new DavClientException("Max retries exceeded for calendar update", retrySignal.failure())));
     }
@@ -184,10 +187,10 @@ private static Mono<Void> handleCalendarObjectUpdateResponse(DavCalendarObject u
                 () -> LOGGER.info("Calendar object '{}' updated successfully.",
                     updatedCalendarObject.uri()));
         } else if (response.status() == HttpResponseStatus.PRECONDITION_FAILED) {
-            return Mono.error(new DavClientException(
+            return Mono.error(new RetriableDavClientException(
                 String.format(
                     "Precondition failed (ETag mismatch) when updating calendar object '%s'. Retry may be needed.",
-                    updatedCalendarObject.uri()), SHOULD_RETRY_CALENDAR_OBJECT_UPDATE));
+                    updatedCalendarObject.uri())));
         } else {
             return Mono.error(new DavClientException(
                 String.format(
diff --git a/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClientException.java b/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClientException.java
index 7313c46002..1107ff641e 100644
--- a/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClientException.java
+++ b/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/DavClientException.java
@@ -19,27 +19,12 @@
 package com.linagora.tmail.dav;
 
 public class DavClientException extends RuntimeException {
-    private final boolean shouldRetry;
 
     public DavClientException(String message) {
-        this(message, false);
-    }
-
-    public DavClientException(String message, boolean shouldRetry) {
         super(message);
-        this.shouldRetry = shouldRetry;
     }
 
     public DavClientException(String message, Throwable cause) {
-        this(message, cause, false);
-    }
-
-    public DavClientException(String message, Throwable cause, boolean shouldRetry) {
         super(message, cause);
-        this.shouldRetry = shouldRetry;
-    }
-
-    public boolean shouldRetry() {
-        return shouldRetry;
     }
 }
diff --git a/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/RetriableDavClientException.java b/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/RetriableDavClientException.java
new file mode 100644
index 0000000000..ddef279952
--- /dev/null
+++ b/tmail-backend/tmail-third-party/openpaas/src/main/java/com/linagora/tmail/dav/RetriableDavClientException.java
@@ -0,0 +1,30 @@
+/********************************************************************
+ *  As a subpart of Twake Mail, this file is edited by Linagora.    *
+ *                                                                  *
+ *  https://twake-mail.com/                                         *
+ *  https://linagora.com                                            *
+ *                                                                  *
+ *  This file is subject to The Affero Gnu Public License           *
+ *  version 3.                                                      *
+ *                                                                  *
+ *  https://www.gnu.org/licenses/agpl-3.0.en.html                   *
+ *                                                                  *
+ *  This program is distributed in the hope that it will be         *
+ *  useful, but WITHOUT ANY WARRANTY; without even the implied      *
+ *  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR         *
+ *  PURPOSE. See the GNU Affero General Public License for          *
+ *  more details.                                                   *
+ ********************************************************************/
+
+package com.linagora.tmail.dav;
+
+public class RetriableDavClientException extends DavClientException {
+
+    public RetriableDavClientException(String message) {
+        super(message);
+    }
+
+    public RetriableDavClientException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}
\ No newline at end of file
diff --git a/tmail-backend/tmail-third-party/openpaas/src/test/java/com/linagora/tmail/dav/DavClientTest.java b/tmail-backend/tmail-third-party/openpaas/src/test/java/com/linagora/tmail/dav/DavClientTest.java
index 94f9a6d406..4c28a1f26e 100644
--- a/tmail-backend/tmail-third-party/openpaas/src/test/java/com/linagora/tmail/dav/DavClientTest.java
+++ b/tmail-backend/tmail-third-party/openpaas/src/test/java/com/linagora/tmail/dav/DavClientTest.java
@@ -52,6 +52,7 @@
 import org.apache.http.HttpStatus;
 import org.apache.james.core.MailAddress;
 import org.apache.james.util.ClassLoaderUtils;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
@@ -79,9 +80,15 @@ public class DavClientTest {
 
     @BeforeEach
     void setup() {
+        System.setProperty("MIN_CALENDAR_OBJECT_UPDATE_RETRY_BACKOFF_IN_MILLS", "10");
         client = new DavClient(davServerExtension.getDavConfiguration());
     }
 
+    @AfterEach
+    void tearDown() {
+        System.clearProperty("MIN_CALENDAR_OBJECT_UPDATE_RETRY_BACKOFF_IN_MILLS");
+    }
+
     @Test
     void existsCollectedContactShouldReturnTrueWhenHTTPResponseIs200() {
         String collectedContactUid = UUID.randomUUID().toString();