Regression testing for mobile web pages or apps is crucial to ensure that updates do not disrupt existing functionalities, especially given the diverse range of devices accessing these applications. This process involves two main phases: initial testing to verify functionality, and subsequent testing to confirm that changes have not introduced new issues. A robust regression testing strategy includes clear entry and exit criteria, which ensure all necessary conditions are met before testing begins and ends. Manual testing remains valuable for detecting issues that automation might miss, though automated regression testing is becoming increasingly important, particularly in Agile environments with tight sprint cycles. This automation can run concurrently with manual testing to enhance productivity. Additionally, random testing simulates real-world scenarios to improve user experience, while effective bug report analysis facilitates quicker resolution of defects. Ultimately, a well-prepared regression testing strategy, encompassing both manual and automated testing, is essential for maintaining application stability and performance across Android and iOS platforms.