is there any way I could download msn on ios?
No… There used to be “Windows Live Messenger” iOS but it was replaced with Skype iOS.
Because of the nature of iOS. There’s no such way to revive MSN for iOS…
I have no idea what API it uses, Possibly 2012’s API.
Currently… Development for reviving 2009 is at a roadblock.
Maybe one can sideload it with Xcode or something?