Seen in the light most favorable to you, that is a very debatable proposition. Mail is one of the base applications for your OS. Base applications tend to be more tightly bond to the OS than optional applications like those in the iWork suite.Because it looks better than a new version.
Because it looks better than a new version.
Or go to preferences in mail and select the viewing tab and click on use classic layout.
I do this before i post this topic.
Why do you want to do this?
mail on 10.8.4 sucks, slow and laggy.
How many accounts with how many emails do you have? What are the specs of your Mac?
I do not use Mail that much, but I have not experienced any lags in 10.8.3, but then again, I have my OS stored on an SSD.