We were recently handed a few blogs/sites to support, that have started way back when wordpress was on v2.1.3 or even 2.0.4
After upgrading the sites to the latest versions (3.4.2 and 3.5) we found that there are files in the root directory as well as the /admin and /includes that are "leftovers" from the older versions or have been relocated in these recent versions. Here is an example of what I am talking about: updated installation - new installation http://db.tt/GpLJr5P9
Some files state: "This file is deprecated and only exists for backwards compatibility"
So... What do you think? Should one just delete these files and go for a beer!!! Should they be left there?
Any concrete/tested answers on the subject?
PS: I am aware of the this post but not quite happy with the answers provided there. Especially when combining this present question with this one about dbdelta. So I am kind of reopening the issue (if I may do so) hoping for a more definite answer.