The September 2016 PU for SharePoint Server 2010, SharePoint Server 2013, and SharePoint Server 2016 introduces the Managed Solutions Gallery to enhance the governance of sandbox solutions.
In a web application with a Managed Solutions Gallery, when you publish an InfoPath form that contains custom code, the form no longer renders in a browser and users can no longer fill in the form using a browser. When you publish an InfoPath form that contains custom code, it creates a category of sandbox solution that cannot be approved using the Managed Solutions Gallery, so publishing fails and the form can no longer be rendered by InfoPath Forms Services.
In a web application with a Managed Solutions Gallery:
Avoid republishing or modifying InfoPath forms that contain custom code. Modifications include changes to the form’s code or to the form itself such as changing a label or modifying the controls on a form.
The creation of new forms that contain code is not possible.
Existing forms that contain code remain functional providing they are not modified.
Forms with code may be added, edited, and republished if those forms will be viewed and filled in using only the client application, InfoPath 2013.
Forms that do not contain code are not affected. You may continue to add, modify, and fill-in forms that do not contain code.