Sorry, but ac1dm4n your post is full of stupid. Firstly, this is an English speaking forum, at least try to make it look like English. Seriously? You have no idea. The same could be said for multiple languages. It's called evolution and adaption. Look at C, Javascript, Visual Basic etc, they all grow with the needs of the community and the languages users. If AU4 isn't backwards compatible, you don't upgrade, nobody forces you to. One of the great features of AutoIt is that you can run multiple versions side by side, therefore, even you install v4 by v3, you can still run old scripts. Edit: Sorry that this post was a tad rude.