diff --git a/build.xml b/build.xml
index eac6eaa8..071c2607 100644
--- a/build.xml
+++ b/build.xml
@@ -100,6 +100,27 @@
     <property file="${env}.properties"/>
     <property file="default.properties"/>
 
+    <!--
+        *******************************************************
+        ***                                                 ***
+        ***   S A M L   O U T P U T   P R O P E R T I E S   ***
+        ***                                                 ***
+        *******************************************************
+    -->
+
+    <!-- Default validUntil duration for all generated metadata, in days. -->
+    <property name="validUntil.default.days" value="14"/>
+
+    <!-- Specific validUntil duration for aggregates, in days. -->
+    <property name="validUntil.aggregate.days" value="${validUntil.default.days}"/>
+    <!-- Same value, as an ISO 8601 duration. -->
+    <property name="validUntil.aggregate.duration" value="P${validUntil.aggregate.days}D"/>
+
+    <!-- Specific validUntil duration for per-entity metadata, in days. -->
+    <property name="validUntil.perEntity.days" value="${validUntil.default.days}"/>
+    <!-- Same value, as an ISO 8601 duration. -->
+    <property name="validUntil.perEntity.duration" value="P${validUntil.perEntity.days}D"/>
+
     <!--
         ***************************************************************
         ***                                                         ***
@@ -1449,6 +1470,8 @@
     <property name="mda.sign.keyAlias" value="${sign.uk.keyAlias}"/>
     <property name="mda.sign.pkcs11Config" value="${sign.uk.pkcs11Config}"/>
     <property name="mda.mdq.output" value="${mdq.output.dir}"/>
+    <property name="mda.validUntil.aggregate.days" value="${validUntil.aggregate.days}"/>
+    <property name="mda.validUntil.perEntity.duration" value="${validUntil.perEntity.duration}"/>
 
     <!--
         Build a property set of all the properties to be passed through, with
diff --git a/mdx/uk/final_tweak.xsl b/mdx/uk/final_tweak.xsl
index c52acc4c..0969ef29 100644
--- a/mdx/uk/final_tweak.xsl
+++ b/mdx/uk/final_tweak.xsl
@@ -44,7 +44,7 @@
         This parameter determines the number of days between the aggregation instant and the
         end of validity of the signed metadata.
     -->
-    <xsl:param name="validityDays" select="14"/>
+    <xsl:param name="validityDays"/>
 
     <xsl:variable name="now" select="date:date-time()"/>
     <xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>
diff --git a/mdx/uk/generate.xml b/mdx/uk/generate.xml
index 0c679ef1..4f140d1c 100644
--- a/mdx/uk/generate.xml
+++ b/mdx/uk/generate.xml
@@ -53,13 +53,7 @@
         final tweaks on the document.
     -->
     <bean id="finalise_parent" abstract="true" parent="mda.XSLTransformationStage"
-        p:XSLResource="classpath:uk/final_tweak.xsl">
-        <property name="transformParameters">
-            <map>
-                <entry key="publisher" value-ref="uk_federation_uri"/>
-            </map>
-        </property>
-    </bean>
+        p:XSLResource="classpath:uk/final_tweak.xsl"/>
 
     <!--
         checkPublishable
@@ -257,6 +251,7 @@
         <property name="transformParameters">
             <map>
                 <entry key="publisher" value-ref="uk_federation_uri"/>
+                <entry key="validityDays" value="${validUntil.aggregate.days}"/>
             </map>
         </property>
     </bean>
@@ -412,6 +407,7 @@
                 <entry key="extraText"
                     value="Central Discovery Service metadata; not for end entity use"/>
                 <entry key="publisher" value-ref="uk_federation_uri"/>
+                <entry key="validityDays" value="${validUntil.aggregate.days}"/>
             </map>
         </property>
     </bean>
@@ -494,6 +490,7 @@
             <map>
                 <entry key="extraText" value="Feature fallback metadata; not for production use"/>
                 <entry key="publisher" value-ref="uk_federation_uri"/>
+                <entry key="validityDays" value="${validUntil.aggregate.days}"/>
             </map>
         </property>
     </bean>
@@ -547,6 +544,7 @@
             <map>
                 <entry key="extraText" value="Feature test metadata; not for production use"/>
                 <entry key="publisher" value-ref="uk_federation_uri"/>
+                <entry key="validityDays" value="${validUntil.aggregate.days}"/>
             </map>
         </property>
     </bean>
@@ -601,6 +599,7 @@
             <map>
                 <entry key="extraText" value="Export metadata for use by partner federations"/>
                 <entry key="publisher" value-ref="uk_federation_uri"/>
+                <entry key="validityDays" value="${validUntil.aggregate.days}"/>
             </map>
         </property>
     </bean>
diff --git a/mdx/uk/mdq-multisign.xml b/mdx/uk/mdq-multisign.xml
index f97e91d3..f834e62a 100644
--- a/mdx/uk/mdq-multisign.xml
+++ b/mdx/uk/mdq-multisign.xml
@@ -67,7 +67,7 @@
                     </constructor-arg>
                 </bean>
                 <bean parent="mda.SetCacheDurationStage" p:cacheDuration="PT6H"/>
-                <bean parent="mda.SetValidUntilStage" p:validityDuration="P14D"/>
+                <bean parent="mda.SetValidUntilStage" p:validityDuration="${validUntil.perEntity.duration}"/>
 
                 <!-- Identity transform fixes signing issues. -->
                 <bean parent="mda.XSLTransformationStage"