The App Store only shows updates for the OS you are using at the moment, in your case Yosemite 10.10.5.
Jan 12, 2018. Sep 03, 2015.
If you want to go to another newer OS that is called an upgrade. This can be done through the App Store using the following link.
High Sierra is the last/ newest OS your Mac can use. Scroll down to Section 4 and click on Get macOS High Sierra.
Make a full back up of your Mac before upgrading.
Check to see with the developers of any third party apps you use that there are updates available so they will continue to work in the new OS. Another thing you need to check is if any printers/ scanners etc you use have updated drivers and software so they too can continue to function in the new OS.
- Mac users running last year's Mavericks, 2012's Mountain Lion, 2011's Lion and even 2009's Snow Leopard are able to download Yosemite from the Mac App Store starting today.
- Jan 25, 2015.
Feb 3, 2019 11:15 PM
macOS Catalina gives you more of everything you love about Mac. Experience music, TV, and podcasts in three all-new Mac apps. Enjoy your favorite iPad apps now on your Mac. Extend your workspace and expand your creativity with iPad and Apple Pencil. And discover smart new features in the apps you use every day. Now you can take everything you do above and beyond.
Check compatibility
If you're using one of these computers with OS X Mavericks or later,* you can install macOS Catalina. Your Mac also needs at least 4GB of memory and 12.5GB of available storage space, or up to 18.5GB of storage space when upgrading from OS X Yosemite or earlier.
MacBook introduced in 2015 or later
MacBook Air introduced in 2012 or later
MacBook Pro introduced in 2012 or later
Mac mini introduced in 2012 or later
iMac introduced in 2012 or later
iMac Pro (all models)
Mac Pro introduced in 2013 or later
* To upgrade from Lion or Mountain Lion, first upgrade to El Capitan, then upgrade to Catalina. To find your macOS version, Mac model, memory, and storage space, choose About This Mac from the Apple menu . If your Mac isn't compatible with macOS Catalina, the installer will let you know. View the complete list of compatible computers.
Make a backup
Before installing any upgrade, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.
Get connected
It takes time to download and install macOS, so make sure that you have a reliable Internet connection. If you're using a Mac notebook computer, plug it into AC power.
Mac App Store Link Yosemite
Download macOS Catalina
If you're using macOS Mojave, get macOS Catalina via Software Update: Choose Apple menu > System Preferences, then click Software Update.
Or use this link to open the macOS Catalina page on the App Store: Get macOS Catalina. Then click the Get button or iCloud download icon.
Begin installation
App Store For Mac
After downloading, the installer opens automatically.
Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.
If the installer asks for permission to install a helper tool, enter the administrator name and password that you use to log in to your Mac, then click Add Helper.
Allow installation to complete
Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs both macOS and related updates to your Mac firmware.
Stay up to date
After installing macOS Catalina, you will be notified when updates to macOS Catalina are available. You can also use Software Update to check for updates: Choose Apple menu > System Preferences, then click Software Update.
Or get macOS Catalina automatically
If you're using OS X El Capitan v10.11.5 or later and your App Store preferences or Software Update preferences are set to download new updates when available, macOS Catalina will download conveniently in the background, making it even easier to upgrade. A notification will inform you when macOS Catalina is ready to be installed. Click Install to get started, or dismiss the notification to install later. When you're ready to install, just open the file named Install macOS Catalina from your Applications folder.
Learn more
Mac App Store Yosemite Download
- If the installer shows a list of apps that are not optimized for your Mac, learn about 32-bit app compatibility, then choose whether to proceed with the installation.
- For the strongest security and latest features, upgrade to macOS Catalina. If you have hardware or software that isn't compatible with Catalina, you might be able to install an earlier macOS, such as Mojave, High Sierra, Sierra, or El Capitan.
- You can also use macOS Recovery to reinstall macOS.