diff --git a/nextcloudappstore/api/v1/release/info.xsd b/nextcloudappstore/api/v1/release/info.xsd
index 46a2e38ce16..7b0a79ccd97 100644
--- a/nextcloudappstore/api/v1/release/info.xsd
+++ b/nextcloudappstore/api/v1/release/info.xsd
@@ -562,6 +562,8 @@
                         maxOccurs="1"/>
             <xs:element name="architecture" type="architecture" minOccurs="0"
                         maxOccurs="unbounded"/>
+            <xs:element name="backend" type="backend" minOccurs="0"
+                        maxOccurs="unbounded"/>
         </xs:sequence>
     </xs:complexType>
 
@@ -758,4 +760,10 @@
                     value="[a-zA-Z_][0-9a-zA-Z_]*(\\[a-zA-Z_][0-9a-zA-Z_]*)*"/>
         </xs:restriction>
     </xs:simpleType>
+
+    <xs:simpleType name="backend">
+        <xs:restriction base="xs:string">
+            <xs:enumeration value="caldav"/>
+        </xs:restriction>
+    </xs:simpleType>
 </xs:schema>
diff --git a/nextcloudappstore/api/v1/release/pre-info.xslt b/nextcloudappstore/api/v1/release/pre-info.xslt
index c6204b7a047..090fc4589d9 100644
--- a/nextcloudappstore/api/v1/release/pre-info.xslt
+++ b/nextcloudappstore/api/v1/release/pre-info.xslt
@@ -136,6 +136,7 @@
             <xsl:copy-of select="lib"/>
             <xsl:copy-of select="owncloud"/>
             <xsl:copy-of select="nextcloud"/>
+            <xsl:copy-of select="backend"/>
         </dependencies>
     </xsl:template>