Compatibility testing is a type of non-functional testing. It is a type of software testing which is done to ensure that the system/application/website built is compatible with various other objects such as other web browsers, operating systems, users and hardware platforms etc.
Compatibility testing is of two types:
1. Forward Compatibility Testing is a type of testing makes sure that the application is compatible with the upcoming or newer versions.
2. Backward Compatibility Testing makes sure that an application which is designed using the latest version of the environment also works in an older version.
Learn more about Compatibility testing