If you're a user of the Amazon AWS Web Services SDK software and are using the PEAR channel for installing the tool, you'll need to check out this new post to the AWS blog about its retirement.
There's been a noticeable wave of popular PHP projects recently announcing that they will no longer support PEAR as an installation method. Because the AWS SDK for PHP provides a PEAR channel, we've been very interested in the discussion in the community on PEAR channel support. PEAR has been one of the many ways to install the AWS SDK for PHP since 2010. While it's served us well, better alternatives for installing PHP packages are now available (i.e., Composer) and literally all of the PEAR dependencies of the AWS SDK for PHP are no longer providing updates to their PEAR channels.
He goes through several of the major dependencies the AWS SDK has (like Phirum, PHPUnit and Guzzle) and how they've announced the retirement of their own PEAR channels. Updates to the AWS SDK PEAR channel will cease on September 15th, 2014 but will still be available for downloads of older versions of the library. He also links to the location of the latest Phar and Zip archives if you'd like to use those.