As the Qlik platform evolves and new functionality and API methods are introduced, Qlik uses three categories to describe the stability, support level, and likelihood of a change of methods, structs, and functions:

• STABLE means that the method is officially supported and not subject to any change going forward. You can entirely rely on using those methods and reach out to Qlik Support if you run into any issues.
• EXPERIMENTAL means that the API function or method is new, less stable, and subject to change in the future more often than other components. They can, however, be used.
• DEPRECATED means that the components should not be used anymore and may be removed in a future version of Qlik Sense.

Qlik is hosting a handy governance website, API insights, which allows you to quickly check which methods, definitions, and general things have changed between updates and version upgrades (http://api-insights.qlik.com/).