diff --git a/datamodels/2.x/itop-bridge-cmdb-ticket/datamodel.itop-bridge-cmdb-ticket.xml b/datamodels/2.x/itop-bridge-cmdb-ticket/datamodel.itop-bridge-cmdb-ticket.xml
index bf56c65ef..41b439a59 100644
--- a/datamodels/2.x/itop-bridge-cmdb-ticket/datamodel.itop-bridge-cmdb-ticket.xml
+++ b/datamodels/2.x/itop-bridge-cmdb-ticket/datamodel.itop-bridge-cmdb-ticket.xml
@@ -307,35 +307,35 @@
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>100</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>110</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="NetworkDevice" _delta="must_exist">
+    <class id="NetworkDevice" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>60</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>70</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="Server" _delta="must_exist">
+    <class id="Server" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>100</rank>
             </item>
             <item id="services_list" _delta="define">
@@ -345,126 +345,126 @@
         </details>
       </presentation>
     </class>
-    <class id="ApplicationSolution" _delta="must_exist">
+    <class id="ApplicationSolution" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>120</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>130</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="Middleware" _delta="must_exist">
+    <class id="Middleware" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>160</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>170</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="DBServer" _delta="must_exist">
+    <class id="DBServer" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>160</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>170</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="WebServer" _delta="must_exist">
+    <class id="WebServer" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>160</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>170</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="PCSoftware" _delta="must_exist">
+    <class id="PCSoftware" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>150</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>160</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="OtherSoftware" _delta="must_exist">
+    <class id="OtherSoftware" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>150</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>160</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="MiddlewareInstance" _delta="must_exist">
+    <class id="MiddlewareInstance" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>110</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>120</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="DatabaseSchema" _delta="must_exist">
+    <class id="DatabaseSchema" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>110</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>120</rank>
             </item>
           </items>
         </details>
       </presentation>
     </class>
-    <class id="WebApplication" _delta="must_exist">
+    <class id="WebApplication" _delta="if_exists">
       <presentation>
         <details>
           <items>
-            <item id="providercontracts_list" _delta="define">
+            <item id="providercontracts_list" _delta="define_if_not_exists">
               <rank>120</rank>
             </item>
-            <item id="services_list" _delta="define">
+            <item id="services_list" _delta="define_if_not_exists">
               <rank>130</rank>
             </item>
           </items>
diff --git a/datamodels/2.x/itop-bridge-cmdb-ticket/model.itop-bridge-cmdb-ticket.php b/datamodels/2.x/itop-bridge-cmdb-ticket/model.itop-bridge-cmdb-ticket.php
new file mode 100644
index 000000000..60130fe12
--- /dev/null
+++ b/datamodels/2.x/itop-bridge-cmdb-ticket/model.itop-bridge-cmdb-ticket.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Copyright (C) 2013-2021 Combodo SARL
+ *
+ * This file is part of iTop.
+ *
+ * iTop is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * iTop 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.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ */
+
+// This file may be amended with XML snippets
+
diff --git a/datamodels/2.x/itop-welcome-itil/model.itop-welcome-itil.php b/datamodels/2.x/itop-welcome-itil/model.itop-welcome-itil.php
new file mode 100644
index 000000000..60130fe12
--- /dev/null
+++ b/datamodels/2.x/itop-welcome-itil/model.itop-welcome-itil.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Copyright (C) 2013-2021 Combodo SARL
+ *
+ * This file is part of iTop.
+ *
+ * iTop is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * iTop 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.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ */
+
+// This file may be amended with XML snippets
+