diff --git a/Documentation/SOGoInstallationGuide.asciidoc b/Documentation/SOGoInstallationGuide.asciidoc
index 8021319dd..20c99fb42 100644
--- a/Documentation/SOGoInstallationGuide.asciidoc
+++ b/Documentation/SOGoInstallationGuide.asciidoc
@@ -3143,6 +3143,11 @@ current version of SOGo from the previous release.
 
 [cols="100a"]
 |=======================================================================
+h|5.1.0
+|The XSRF protection is now enabled by default in SOGo. If you use a single
+sign-on mechanisim such as C.A.S. or SAML2, you need to disable XSRF by adding
+`SOGoXSRFValidationEnabled = NO` to your configuration file.
+
 h|5.0.0
 |Peer is now verified for TLS connections (SMTP/IMAP/Sieve). If you enabled
 TLS on the local machine (localhost and similar), you need to disable peer