Consider the following scenario:
You create a mobile device mailbox policy with an attachment size limit of 1MB and assign that policy to a user.
You set up an account on an iOS device and send an email message that has a 2MB attachment to that account.
You download the attachment from the iOS client.
In this scenario, you can download and view the attachment without an error message.
This issue occurs because the mobile device mailbox policy isn't enforced.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.