Is OSX Yosemite outdated?
Support Ending December 31, 2019. Apple has announced the launch of its new operating system, macOS 10.15 Catalina in October 2019. In keeping with Apple's release cycle, macOS 10.10 Yosemite is no longer receiving security updates as of November of 2015.
When did Yosemite 10.10 come out?
Version 10.10: "Yosemite"
OS X Yosemite was released to the general public on October 16, 2014, as a free update through the Mac App Store worldwide.