I am using unreal videos to learn in iMac but some of the vides seems outdated.

Yes those videos but also the videos in this playlist:

While some of the videos are older, they are pretty good about putting annotations on the screen when something has changed with the version. So as long as you can see annotations you will see if/when something may have changed. If there are no annotations then it’s pretty safe to assume that the content in the video is still relevant. It’s much easier and cheaper to add an annotation on the screen than it is too re-produce the video content; especially since very few things change on the surface per update.