Update overview.md

Author: GennadNY

articles/postgresql/flexible-server/overview.md

@@ -119,6 +119,8 @@ One advantage of running your workload in Azure is global reach. The flexible se
 | West US 2 | :heavy_check_mark: | :heavy_check_mark: | :x: |
 
 <!-- We continue to add more regions for flexible server. -->
+> [!NOTE]
+> If your application requires Zone redundant HA and its not available in your preferred Azure region, as we continue adding this functionality to more regions, please consider using other regions within the same geography where Zone redundant HA is available, i.e. US East for US East 2, Central US for North Central US, etc. 
 
 ## Migration