Updating mac OS X software 10.9.5 to 10.10.0

You're supposed to use Photos instead of iPhoto.

Photo Booth is an OS component and should have been upgraded with it.

For iMovie and other applications, go to their product page in the new country's store and get them.

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Back up your data, check your applications for compatibility, and depending on which Mac model you have, download El Capitan, High Sierra, or Mojave from the Mac App Store.

Yosemite will only be available by logging in with an Apple ID previously used to download it and clicking on the Purchases tab.

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Mac OS X Yosemite is no ;longer offered for download. Depending on which Mac you have and its age determines what OS you can upgrade to.

If your Mac meets the requirements you can upgrade to Mojave, How to upgrade to macOS Mojave - Apple Support

if you can't upgrade to Mojave then High Sierra is still available. How to upgrade to macOS High Sierra - Apple Support

and if you cannot upgrade to High Sierra El Capitan is available, How to upgrade to OS X El Capitan - Apple Support

Before you upgrade make a full back up of your Mac, check that any third party software you use has updates available for the new OS, the same goes for printer and scanner drivers.