A method and computer-readable-medium for installing a patch to a computer application program based on the criticality of the patch and the execution format of the computer application are disclosed. An installer program installs application programs. The installer program also-stores related information, including an execution format, in a configuration database. The execution format is either Run-Locally or Run-From-Source. If the execution format is Run-From-Source, the application or features that are designated as Run-From-Source are read-only and are executed from a source, such as from a CD-ROM. Since Run-From-Source executions run from a read-only source, patches cannot be directly applied. When a patch is authored, information as to the criticality of the patch is stored with the patch. Preferably, the criticality is specified based on a feature. When an installer program applies a patch, the installer program queries the execution format. Any features that are Run-Locally can be patched. If a feature is Run-From-Source, a query is made as to whether the feature is critical. If the patch is critical for a feature, the feature is installed, the execution format is changed to Run-Locally, and the patch is applied. If the patch is not critical for a Run-From-Source feature, the patch is not applied. The configuration database is updated during processing to reflect what features have been patched, and what features have not been patched.