Are you sure it's Android 4.5? Officially, Android went from 4.4.x to 5.0. If your system OS says Android 4.5 then you've got something that's akin to a platypus crossed with a unicorn. Without looking at the file level OS, there's no telling what you've really got. I do agree with
@mikedt that the pop-up is more likely developer laziness (or incompetence) than anything else. The pop-ups, ads, etc are probably also the result of adware installed as a system app.
Personally, if you want a beater phone, I'd head over to swappa and pick up any of a handful of phones for under $50 and send that Chinese monstrosity to the recycler.