Upgrading from PEAR 1.3.2

Hi all, I run a company server with PEAR 1.3.2 and PHP 4.3.9. Yeah, it's ancient, but things run smooth as silk. Anyways, I was wondering after reading this: http://pear.php.net/news/package.xml.1.0.php If I upgrade PEAR, will it break any of my existing packages (which are also old, but work great)? Currently:

Archive_Tar               1.1     stable
Auth                      1.2.3   stable
Console_Getopt            1.2     stable
DB                        1.6.2   stable
HTML_AJAX                 0.5.0   beta
HTML_Common               1.2.2   stable
HTML_Form                 1.3.0   stable
HTML_QuickForm            3.2.5   stable

HTML_QuickForm_Controller 1.0.5 stable

HTML_Table                1.6.1   stable
HTTP                      1.2.2   stable
HTTP_Upload               0.9.1   stable
Mail                      1.1.3   stable
Net_SMTP                  1.2.3   stable
Net_Socket                1.0.1   stable
PEAR                      1.3.2   stable
Pager                     2.3.4   stable
XML_Parser                1.0.1   stable
XML_RPC                   1.1.0   stable

Any guidance would be greatly appreciated! The server has lots of sites on it that depend on PEAR, and I don't want anything to go down because of a sloppy upgrade. Cheers, Matt