Merge pull request #10894 from m-nestorovic/patch-15

Update New-TransportRule.md

Author: chrisda

exchange/exchange-ps/exchange/New-TransportRule.md

@@ -931,12 +931,16 @@ This parameter specifies a condition or part of a condition for the rule. The na
 
 In on-premises Exchange, this condition is only available on Mailbox servers.
 
-The AttachmentIsUnsupported parameter specifies a condition that looks for unsupported file types in messages. Unsupported file types are message attachments that aren't natively recognized by Exchange, and the required IFilter isn't installed. Valid values are:
+The AttachmentIsUnsupported parameter specifies a condition that looks for unsupported file types in messages. Valid values are:
 
 - $true: Look for unsupported file types in messages.
 - $false: Don't look for unsupported file types in messages.
 
-For more information, see [Register Filter Pack IFilters with Exchange 2013](https://learn.microsoft.com/exchange/register-filter-pack-ifilters-with-exchange-2013-exchange-2013-help).
+Rules can inspect the content of supported file types only. If the rule finds an attachment file type that isn't supported, the AttachmentIsUnsupported condition is triggered. 
+
+For the list of supported file types, see [Supported file types for mail flow rule content inspection](https://learn.microsoft.com/exchange/security-and-compliance/mail-flow-rules/inspect-message-attachments#supported-file-types-for-mail-flow-rule-content-inspection).
+
+In Exhange 2013, to extend the list of supported file types, see [Register Filter Pack IFilters with Exchange 2013](https://learn.microsoft.com/exchange/register-filter-pack-ifilters-with-exchange-2013-exchange-2013-help).
 
 ```yaml
 Type: Boolean