diff --git a/build/test_master_unsigned.xsl b/build/test_master_unsigned.xsl
index 769e13fb..27ec4c9a 100644
--- a/build/test_master_unsigned.xsl
+++ b/build/test_master_unsigned.xsl
@@ -33,7 +33,7 @@
 		This parameter determines the number of days between the aggregation instant and the
 		end of validity of the signed metadata.
 	-->
-	<xsl:variable name="validityDays" select="14"/>
+	<xsl:param name="validityDays" select="14"/>
 	
 	<xsl:variable name="now" select="date:date-time()"/>
 	<xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>
diff --git a/build/uk_master_back.xsl b/build/uk_master_back.xsl
index 5731da6a..13f39999 100644
--- a/build/uk_master_back.xsl
+++ b/build/uk_master_back.xsl
@@ -38,7 +38,7 @@
 		This parameter determines the number of days between the aggregation instant and the
 		end of validity of the signed metadata.
 	-->
-	<xsl:variable name="validityDays" select="14"/>
+	<xsl:param name="validityDays" select="14"/>
 	
 	<xsl:variable name="now" select="date:date-time()"/>
 	<xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>
diff --git a/build/uk_master_export.xsl b/build/uk_master_export.xsl
index 4feb6dbe..627bd4c7 100644
--- a/build/uk_master_export.xsl
+++ b/build/uk_master_export.xsl
@@ -35,7 +35,7 @@
 		This parameter determines the number of days between the aggregation instant and the
 		end of validity of the signed metadata.
 	-->
-	<xsl:variable name="validityDays" select="14"/>
+	<xsl:param name="validityDays" select="14"/>
 	
 	<xsl:variable name="now" select="date:date-time()"/>
 	<xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>
diff --git a/build/uk_master_test.xsl b/build/uk_master_test.xsl
index a463ec5d..885116a2 100644
--- a/build/uk_master_test.xsl
+++ b/build/uk_master_test.xsl
@@ -37,7 +37,7 @@
 		This parameter determines the number of days between the aggregation instant and the
 		end of validity of the signed metadata.
 	-->
-	<xsl:variable name="validityDays" select="14"/>
+	<xsl:param name="validityDays" select="14"/>
 	
 	<xsl:variable name="now" select="date:date-time()"/>
 	<xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>
diff --git a/build/uk_master_unsigned.xsl b/build/uk_master_unsigned.xsl
index a8e26287..faf8078a 100644
--- a/build/uk_master_unsigned.xsl
+++ b/build/uk_master_unsigned.xsl
@@ -34,7 +34,7 @@
 		This parameter determines the number of days between the aggregation instant and the
 		end of validity of the signed metadata.
 	-->
-	<xsl:variable name="validityDays" select="14"/>
+	<xsl:param name="validityDays" select="14"/>
 	
 	<xsl:variable name="now" select="date:date-time()"/>
 	<xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>