The web browser, Google Chrome, will continue to function on Windows XP, Windows Vista, as well as Mac OS X 10.6, 10.7, and 10.8. However as of April 2016 Google will no longer provide support with updates and security fixes as these platforms are no longer actively supported by Microsoft and Apple. These older platforms are no longer receiving their own critical security updates and face a greater potential to be infected with viruses and malware.
If you are still using these platforms, it is highly recommended that you move to a newer operating system to ensure that you continue to receive the latest Chrome versions and features as well as the Microsoft/Apple necessary security updates. Keep in mind, Windows Vista will be receiving security patches until April of 2017, however Google will not be providing security patches for the entire year before Vista’s end of support date.