Netflix will only stream 1080p on Microsoft Edge or IE11

Yes, this is true, except that Internet Explorer also plays 1080p just fine; try it and see, if you don't believe me ^^' . It's also been true for months, and there's nothing unclear about it.

The reason is quite simple: The standards for HTML5 streaming are only finalized up to 720p, and MOST browsers follow the standards. Microsoft, however, has never been particularly good at following any standard they didn't come up with themselves, and furthermore, this is an opportunity to try to scavenge some market share for their terrible browsers. Safari has the same niche in the Mac camp, from what I've seen online, but I don't use Macs, so YMMV.

Firefox and its variants (Pale Moon, Waterfox, et al.), Opera, and Chrome all are standards-compliant, so they won't have 1080p HTML5 playback until everything is finished. Flash still works just fine for HD content, but sadly, most big video providers don't use Flash any more. This is understandable, as Flash is a dumpster-fire of security holes and bugs, but leaves us without 1080p until everything is completed.

Such a shame that MS is so desperately trying to reacquire some IE/Edge marketshare.

Sadly, 1080p streaming via Netflix is not that necessary to endure IE/Edge possible pop-ups and moreover, the difference is not night and day and rather negligible.

I hate everything about IE and Edge but I truly love Microsoft and their product line.