What is the meaning of the phrase: "The malware affects IE9 through IE11(Internet Explorer)"? Why can't we use "from IE9 to IE11" instead?
"The malware affects from IE9 to IE11" sounds really strange to me in American English. The only example I can think of where the construct "verb from x to y" sounds "correct" when defining an inclusive set would be "awake from dusk to dawn". I don't think most American English speakers or writers would use that instead of "verb x through y" when they mean to include the x and y as part of the set.
Saying "The malware affects IE9 through IE11" is more technically accurate to me, since you are unambiguously saying that IE9 is affected, IE11 is affected, and so are all the versions in between. And you get to trim a word from the sentence!
"To" indicates that the stopping point of the iterative count ends before ie11 begins. "Through" includes ie11 in the count.
That is to say using only integers, and excluding fractions 1 to 10 is the same as 1 through 9.
The easiest way to see the difference is with time. If you work from 1 to 5, you've worked 4 hours, because you stop at 5 without going through it. The five o'clock hour isn't included. If you work from 1 through 5, you're off work at about 6.