It works with everything from XP right through to 10

.
IE11 is far better than 10 and below, by miles. However, Windows 10 on the other hand, should be given a wide birth unless you're on 8.1.
If you want to ensure you can upgrade, image the current Windows install, then do an upgrade. If you want to go back, you can always image the 10 install, then restore the earlier image you took prior to upgrading.