diff --git a/datamodels/2.x/itop-core-update/en.dict.itop-core-update.php b/datamodels/2.x/itop-core-update/en.dict.itop-core-update.php
index 4f9b6f2cb..ea7b476ed 100644
--- a/datamodels/2.x/itop-core-update/en.dict.itop-core-update.php
+++ b/datamodels/2.x/itop-core-update/en.dict.itop-core-update.php
@@ -20,7 +20,6 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with iTop. If not, see <http://www.gnu.org/licenses/>
  */
-
 Dict::Add('EN US', 'English', 'English', array(
 	'iTopUpdate:UI:PageTitle' => 'Application Upgrade',
     'itop-core-update:UI:SelectUpdateFile' => 'Application Upgrade',
@@ -43,6 +42,7 @@ Dict::Add('EN US', 'English', 'English', array(
 	'iTopUpdate:UI:DoFilesArchive' => 'Archive application files',
 	'iTopUpdate:UI:UploadArchive' => 'Select a package to upload',
 	'iTopUpdate:UI:ServerFile' => 'Path of a package already on the server',
+	'iTopUpdate:UI:WarningReadOnlyDuringUpdate' => 'During the upgrade, the application will be set in mode read-only.',
 
     'iTopUpdate:UI:Status' => 'Status',
     'iTopUpdate:UI:Action' => 'Update',
diff --git a/datamodels/2.x/itop-core-update/fr.dict.itop-core-update.php b/datamodels/2.x/itop-core-update/fr.dict.itop-core-update.php
index 81adc100a..34f187d20 100644
--- a/datamodels/2.x/itop-core-update/fr.dict.itop-core-update.php
+++ b/datamodels/2.x/itop-core-update/fr.dict.itop-core-update.php
@@ -42,6 +42,7 @@ Dict::Add('FR FR', 'French', 'Français', array(
 	'iTopUpdate:UI:DoFilesArchive' => 'Archive les fichiers de l\'application',
 	'iTopUpdate:UI:UploadArchive' => 'Choisir un package à télécharger',
 	'iTopUpdate:UI:ServerFile' => 'Chemin d\'un package présent sur le serveur',
+	'iTopUpdate:UI:WarningReadOnlyDuringUpdate' => 'Pendant toute la durée de la mise à jour, l\'application sera en lecture seule.',
 
     'iTopUpdate:UI:Status' => 'Versions installées',
     'iTopUpdate:UI:Action' => 'Mettre à jour',
diff --git a/datamodels/2.x/itop-core-update/view/ConfirmUpdate.html.twig b/datamodels/2.x/itop-core-update/view/ConfirmUpdate.html.twig
index 38ed9e5d7..50aef4d51 100644
--- a/datamodels/2.x/itop-core-update/view/ConfirmUpdate.html.twig
+++ b/datamodels/2.x/itop-core-update/view/ConfirmUpdate.html.twig
@@ -67,7 +67,11 @@
 
         <fieldset>
             <legend>{{ 'iTopUpdate:UI:Action'|dict_s }}</legend>
-
+            <div class="header_message message_info">
+                <div>
+                    <span>{{ 'iTopUpdate:UI:WarningReadOnlyDuringUpdate'|dict_s }}</span>
+                </div>
+            </div>
             <div>
                 <table>
                     <tr>