It refers to the fact that a certain software can work stably in several operating systems without unexpected problems such as exit.

Not every software should be tested for all compatibility projects. In the actual test, the selection should be made according to the software type, requirement positioning and test environment, and the test scheme should be expanded based on this idea.

Compatibility testing should fully validate the application scope of the software definition and provide developers and users with confidence in the use of the software. But because compatibility testing requires a large investment, test managers must make trade-offs to get the best results with a small investment.

It should also be noted that for custom systems, compatibility testing should be done as early as possible, or the risk and investment of compatibility testing will increase as more data is added to the system after it is put into use.