diff --git a/core/datamodel.core.xml b/core/datamodel.core.xml
index 445a7fbf2..c6d2b18c9 100644
--- a/core/datamodel.core.xml
+++ b/core/datamodel.core.xml
@@ -282,6 +282,11 @@
           <field id="obj_attcode" xsi:type="AttributeString"/>
         </fields>
       </class>
+      <class id="DefaultWorkingTimeComputer" _delta="define">
+        <interfaces>
+          <interface id="iWorkingTimeComputer"/>
+        </interfaces>
+      </class>
     </classes>
     <attribute_properties_definition _delta="define">
       <properties>
diff --git a/datamodels/2.x/itop-sla-computation/datamodel.itop-sla-computation.xml b/datamodels/2.x/itop-sla-computation/datamodel.itop-sla-computation.xml
new file mode 100644
index 000000000..c6e47cac5
--- /dev/null
+++ b/datamodels/2.x/itop-sla-computation/datamodel.itop-sla-computation.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<itop_design xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="3.2">
+  <meta>
+    <classes>
+      <class id="SLAComputation" _delta="define">
+        <interfaces>
+          <interface id="iWorkingTimeComputer"/>
+        </interfaces>
+      </class>
+    </classes>
+  </meta>
+</itop_design>
\ No newline at end of file