Hi Mark, I do not have experience with proxys, but this should work like a normal internet connection right. However when using native widgets, i.e. push notifications, this might interfere with proxys/firewalls.
What I would do is test some scenarios. You can get the Mendix mobile app from Google play store, and try some examples of mobile apps in the Showcase section. Let us know your findings.
Thanks Wilfried. In our case the app does not use push notifications. Only mobile camera. I tested an hybrid app without proxy, with proxy and with incorrect proxy settings (to confirm that is failing); results are fine. The Mendix app respects the Wifi's advanced proxy settings, so using proxy is working.