Problems on latest versions of iOS Safari (maybe just from 14 on)

[ioliva]

We have experienced that, at least on iOS 14 Safari, as the window.open mechanism is used, a new browser session is started, and that breaks our download, since we require user to be logged in (the session should be the same as the previous one).

We have found that all works flawlessly if we use the same iframe mechanism as if it weren't iOS (we avoid setting isIos = true). Also, the UX is much better, since the user does not see a new tab opening that he/she should close manually afterwards.