Microsoft XML Parser (MSXML) 4.0 updates are distributed in service packs. Service packs help keep MSXML current, and also extend and update the functionality of your computer. Service packs are cumulative--each new service pack contains all the fixes that are included with previous service packs and any new fixes. You do not have to install a previous version of a service pack before you install the latest version. For example, you do not have to install MSXML 4.0 Service Pack 1 (SP1) before you install MSXML 4.0 Service Pack 2 (SP2) because SP2 contains all the fixes that are in SP1.
When a new MSXML service pack is released, the previous service pack is removed from the Web.
When a new MSXML service pack is released, the previous service pack is removed from the Web.