diff --git a/docs/simplesamlphp-idp.txt b/docs/simplesamlphp-idp.txt
index d82ba8dcce8910f6b914a461b7ceb2896dd0c366..3266397bfd42779627f7505c7bfffa299567874d 100644
--- a/docs/simplesamlphp-idp.txt
+++ b/docs/simplesamlphp-idp.txt
@@ -150,7 +150,8 @@ files, see the [IdP hosted reference](simplesamlphp-reference-idp-hosted).
 Using the `uri` NameFormat on attributes
 ----------------------------------------
 
-It is generally recommended to use the `urn:oasis:names:tc:SAML:2.0:attrname-format:uri` attribute NameFormat in new installations.
+The [interoperable SAML 2 profile](http://saml2int.org/profile/current) specifies that attributes should be delivered using the `urn:oasis:names:tc:SAML:2.0:attrname-format:uri` NameFormat.
+We therefore recommended enabling this in new installations.
 This can be done by adding the following to the saml20-idp-hosted configuration:
 
     'AttributeNameFormat' => 'urn:oasis:names:tc:SAML:2.0:attrname-format:uri',