The version of the iTunes Movie Trailer app has NOT changed or has been recently updated.
The Version of iTunes Movie Trailers App was changed in November-2017 if you go through the Version History on the APP page, and I was using an older version which dates back even earlier than that, and like I said before it did have an option to select if you wanna see it in SD or HD in the older version the one which I was using.
The minimum iOS version is still iOS 9 and later iOS versions.
Exactly my point, I was breaking head over heels explaining someone at Apple Tech Support and she was just going on and on explaining me that since I am on iOS 9.3.5 could be one of the reason that I am no longer seeing that option ? They are saying that since there has been a version update to this APP and now it is only compatible with the latest version of iOS certain features are gonna be taken away and certain are added, but no where in the version history does it mention that the SD or HD feature will not work on iOS 9.3.5 like you found out, the minimum iOS requirement for this APP is iOS 9 which is also what I tried to explain her !! It is a free APP and it is developed by Apple. Surprisingly there is no email anywhere on the APP page, to send an email to the developers of this APP and ask them, which normally all third part app developers put their email, shocking Apple is not following its own set best practices.
It's still version 1.4.4 and this version runs on both my iPad 2 AND my iPad Pro on iOS 11.
It has been Version 1.4.4 only since November-2017 not before that, and I was using an older version, I just updated Yesterday to 1.4.4 even if it was released in November-2017
I see no difference in this app on either iOS versions.
You would only see the difference had you had, the older version which had the Playback option of Playing in SD or HD. I have had this APP since 5 years, believe me it was different earlier.