Support Ending December 31, 2019In keeping with Apple's release cycle, macOS 10.10 Yosemite is no longer receiving security updates as of November of 2015. Our latest fully-supported operating system is macOS Mojave (10.14).
Luckily, if you're already running Mavericks (Mac OS X 10.9) on your Mac, that same Mac is compatible with Yosemite—Mavericks and Yosemite have the same system requirements. Apple confirmed that your Mac requires 2GB of RAM and 8GB of free storage space for the installation.
The Latest Version is macOS Big SurApple's newest Mac operating system is macOS 11.0, also known as macOS Big Sur. This is the sixteenthmajor release of the Mac operating system. macOS 11.0 Big Sur drops support for some Macs that ran macOS 10.15 Catalina.
Support Ending December 31, 2019In keeping with Apple's release cycle, macOS 10.09 Mavericks is no longer receiving security updates as of November of 2014. Our latest fully-supported operating system is macOS Mojave (10.14).
What You Need to Upgrade to macOS Mavericks. A copy of the macOS Mavericks installer, which you can obtain from the Mac App Store. Remember, in order to access the store, you must be running macOS Snow Leopard or later. A startup drive with sufficient space for the Mavericks installation.
Make sure you're ready to upgrade.Before you upgrade, we recommend that you back up your Mac. Then, if your Mac is running OS X Mavericks 10.9 or later, you can upgrade directly to macOS Catalina.
Apple OS X Mavericks is version 10.9 of the OS X computer operating system. New features in OS X Mavericks include inactive memory compression, enhanced support for multiple displays and iCloud Keychain, a built-in password generation, storage and security application.
Make sure your Mac Pro is on the same Wi-Fi network as your external storage device, or connect the storage device to your Mac Pro. Open System Preferences, click Time Machine, then select Back Up Automatically. Select the drive you want to use for backup, and you're all set.
Download macOS Big SurIf you're using macOS Mojave or later, get macOS Big Sur via Software Update: Choose Apple menu  > System Preferences, then click Software Update. Or use this link to open the macOS Big Sur page on the App Store: Get macOS Big Sur. Then click the Get button or iCloud download icon.
Apple security updates
| Name and information link | Available for | Release date |
|---|
| macOS Big Sur 11.3.1 | macOS Big Sur | 03 May 2021 |
| iOS 14.5.1 and iPadOS 14.5.1 | iPhone 6s and later, iPad Pro (all models), iPad Air 2 and later, iPad 5th generation and later, iPad mini 4 and later, and iPod touch (7th generation) | 03 May 2021 |
Check compatibilityThe version of macOS that came with your Mac is the earliest version it can use. For example, if your Mac came with macOS Big Sur, it will not accept installation of macOS Catalina or earlier. If a macOS can't be used on your Mac, the App Store or installer will let you know.
OS X Mavericks (version 10.9) is the tenth major release of macOS, Apple Inc.'s desktop and server operating system for Macintosh computers. OS X Mavericks was announced on June 10, 2013, at WWDC 2013, and was released on October 22, 2013 worldwide.
The Big Sur support document specifies 44.5GB is required if you are upgrading from 10.10 Yosemite or 10.11 El Capitan, and your Air must be 2013 or newer (you omitted to mention the year of your MacBook Air). "If upgrading from macOS Sierra or later, macOS Big Sur requires 35.5GB of available storage to upgrade.
Just keep in mind, Apple only releases security patches for the most recent OS plus the two prior which means the following OSes are secure through: OS X 10.10 Yosemite: 2017.
Mac OS X 10.10. 5 was an update to Mac OS X 10.10 released on August 13, 2015. This update includes the following: Improves compatibility with certain email servers when using Mail.
