The UPSC updates its examination pattern or syllabus primarily when necessary, typically occurring every few years. Significant changes can also be prompted by shifts in government policies or educational reforms. The last substantial update was noted in 2013, when the introduction of General Studies papers took place. However, it's crucial for aspirants to regularly check the official UPSC website or notifications for any updates, as these changes can affect preparation strategies and the focus areas within the examination syllabus.