Apple has removed this critical feature from iTunes as they expect you to just use the iOS App Store app to manage your apps.
This means then all those old apps that were removed from the App Store are forever gone unless you back up your .IPA file (typically saved in "X:\Music\iTunes\iTunes Media\Mobile Applications" for windows users).
Even of more critical import (and pun intended), the ability to import files via drag and drop using iTunes is now missing. IE. You can no longer plug in your iPad, load up iTunes and then drag in all those home movies and other video files you created into an app like VLC. Same goes with productivity apps like GoodReader or iXpenseIt.
I would recommend that you DO NOT install this version of iTunes 12.7 (for Windows - not sure what the Mac version is up to). If you are forced to because you purchased the new iPhone 8/8 plus/X then maybe consider installing the new iTunes on another PC or Mac purely for the full backup functionality and I guess music management but otherwise hope that you can use the older version to manage your apps. I suspect not as I do not have the new iPhone yet (waiting for X still but may not bother with this removal of App management in iTunes and TouchID).