The July release brings some interesting features. One of those is the ability to create attachment rules on Nintex Forms for Office 365.
Once you open your newly created form on O365, you see only the title and attachment displayed, right?
When you select your attachment control, you'll open the attachment control configuration screen, and notice it has changed slightly. In addition to the previous 3 panels, you have now, the "validation" section. yeaaaaah!
Basically the validation section allows you to create the following rules :
Note that for those amount you still can use item properties or inline functions to provide a dynamic amount of attachments according to your item!
So now you can say that you want between 1 and 4 attachement files and they have to be Pdf or Word docs!!