Later on Wednesday, Apple will stop allowing people running version 4.2 to purchase songs from the iTunes Music Store.
"As of today, customers will need to use one of the three most recent versions of iTunes--4.7, 4.6 or 4.5--to continue purchasing and downloading songs," Apple said in a statement provided to CNET News.com.
The company, which, downplayed the impact of the move.
"Less than 5 percent of all iTunes customers are using the old iTunes 4.2 version, so asking them to upgrade to the free iTunes 4.7 is no big deal," Apple said.
When Apple released version 4.5 in April, the company disabled support for a number of programs that tried to expand iTunes music sharing beyond the streaming of music files. And with the new version 4.7 that Applelast week, the company support for iPodDownload, a program that let customers copy music from an iPod into their iTunes library.
Apple touted the benefits of later versions, including features such as iMix, Party Shuffle and CD Insert Printing. The version also is required to support the features of the iPod Photo.