add drs 2.2 note

Author: halkazwini

articles/web-application-firewall/afds/waf-front-door-drs.md

@@ -88,6 +88,9 @@ If you're upgrading, or assigning a new ruleset version, and would like to prese
 
 ### DRS 2.2
 
+> [!IMPORTANT]
+> Currently, you can't assign DRS 2.2, even though it's shown as available in the Azure portal.
+
 DRS 2.2 rules offer better protection than earlier versions of the DRS. It includes other rules developed by the Microsoft Threat Intelligence team and updates to signatures to reduce false positives. It also supports transformations beyond just URL decoding.
 
 DRS 2.2 includes 18 rule groups, as shown in the following table. Each group contains multiple rules, and you can customize behavior for individual rules, rule groups, or an entire rule set. DRS 2.2 is baselined off the Open Web Application Security Project (OWASP) Core Rule Set (CRS) 3.3.4 and includes additional proprietary protections rules developed by Microsoft Threat Intelligence team.