Contributed By: Cliff Hobbs [MVP SMS]
The following setup scenarios apply to all SMS service Packs unless explicitly stated otherwise.

The Setup program for SMS Service Packs supports:

• Upgrading an existing Primary Site that is running SMS 2.0 SP2 or later
• Upgrading an existing Secondary Site that is running SMS 2.0 SP2 or later
• Installing a new Secondary Site
• Upgrading an existing SMS Administration console that already has a version that is SMS 2.0 SP2 or later
• Installing the SMS Administration console on a machine that hasn’t had it installed before
• Modify an SMS Administration console
• Removing the Service Pack in question (so if you’ve installed SP5 you can remove SP5)
• Reset or modify an SMS 2.0 Site that is running the same Service Pack level in question (so you can’t use the SP4 Setup program to reset or modify an SP5 installation)

SMS setup does NOT support:

• Installing a Primary Site without that Primary already running SMS 2.0 SP2 or later
• Adding an SMS Administrator Console or optional components to an SMS site that is running an earlier version than the Service Pack level you’re applying (so you can’t add an SMS Administrator Console or optional components to an SMS 2.0 SP2 Site using SP3)
• Installing if the Service Pack level already applied is greater than the version you’re trying to install (for example if you try to run the SP4 Setup program on a server that is running SP5 the installation will fail)