New file types will be added into the block file type list.
Based on Microsoft’s evaluation, these file types are rarely used.
If one of these file types is already added into your allowed list, it will not be added into the blocked list.
The below table lists the new file type being blocked:
|File type (extension)||Used for/by|
If you want to continue to allow these, you can update your allowed list using the PowerShell command
$policy = Get-OwaMailboxPolicy [policy name]
$allowedFileTypes = $policy.AllowedFileTypes
$allowedFileTypes.Add(“[file type to be added – like .cer]”)
Set-OwaMailboxPolicy $policy -AllowedFileTypes $allowedFileTypes