diff --git a/mdx/uk/final_tweak.xsl b/mdx/uk/final_tweak.xsl
index f8afebff..8d42588e 100644
--- a/mdx/uk/final_tweak.xsl
+++ b/mdx/uk/final_tweak.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:param name="validityDays" select="14"/>
+	<xsl:param name="validityDays" select="21"/>
 	
 	<xsl:variable name="now" select="date:date-time()"/>
 	<xsl:variable name="validUntil" select="mdxDates:dateAdd($now, $validityDays)"/>