Question about upgrading Crystal Reports Runtime

My server is installed with crystal report 2008 runtime sp1, and I want to upgrade it to runtime sp4 version. I try to download and install CR 2008 runtime sp2, it said "Another version of this product is already installed and installation of this version cannot continue". So can I just install cr 2008 runtime sp4 in order to finish the upgrade and does runtime sp4 version include all the previous FixPacks ?

My server is using Windows Server 2003 r2 sp2.