2.4.1 Triggers for Maintenance

There are several reasons why software maintenance, and thus maintenance testing, takes place, both for planned and unplanned changes.

We can classify the triggers for maintenance as follows:

• Modification, such as planned enhancements (e.g., release-based), corrective and emergency changes, changes of the operational environment (such as planned operating system or database upgrades), upgrades of COTS software, and patches for defects and vulnerabilities

• Migration, such as from one platform to another, which can require operational tests of the new environment as well as of the changed software, or tests of data conversion when data from another application will be migrated into the system being maintained

  • Retirement, such as when an application reaches the end of its life. When an application or system is retired, this can require testing of data migration or archiving if long dataretention periods are required.

  • Testing restore/retrieve procedures after archiving for long retention periods may also be needed.

  • Regression testing may be needed to ensure that any functionality that remains in service still works.

For Internet of Things systems, maintenance testing may be triggered by the introduction of completely new or modified things, such as hardware devices and software services, into the overall system. The maintenance testing for such systems places particular emphasis on integration testing at different levels (e.g., network level, application level) and on security aspects, in particular those relating to personal data.