To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.
Change Date Terminal Mac El Capitan Update

Learn how to upgrade to macOS Big Sur, the latest version of macOS.
Check compatibility

The 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. For example, it might say that it's not compatible with this device or is too old to be opened on this version of macOS. To confirm compatibility before downloading, check the minimum hardware requirements:
- macOS Catalina 10.15 hardware requirements
- macOS Mojave 10.14 hardware requirements
- macOS High Sierra 10.13 hardware requirements
- macOS Sierra 10.12 hardware requirements
- OS X El Capitan 10.11 hardware requirements
- OS X Yosemite 10.10 hardware requirements
Download macOS using Safari on your Mac
Made a bootable El Capitan USB. Press Option key and boot from El Capitan USB; Go to Utilities, Open Terminal, set date to, (that is July 06, 2017 at 10:50am; date is set about over 2 years prior current date, I just pick a random day in mid 2017 as suggested by Charlee78), exit Terminal. I often have to switch between timezones to test our timezone-sensitive application code. I was getting annoyed at having to open the settings screen in preferences (which is slow) and found out how to do it from the command line.To set your timezone run:sudo systemsetup -settimezone timezoneWhere timezone is a valid zone from this list:sudo systemsetup -listtimezonesFinally, you can get your.
Safari uses these links to find the old installers in the App Store. After downloading from the App Store, the installer opens automatically.
- macOS Catalina 10.15 can upgrade Mojave, High Sierra, Sierra, El Capitan, Yosemite, Mavericks
- macOS Mojave 10.14 can upgrade High Sierra, Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
- macOS High Sierra 10.13 can upgrade Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion

Safari downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.
El Capitan Software Download
- macOS Sierra 10.12 can upgrade El Capitan, Yosemite, Mavericks, Mountain Lion, or Lion
- OS X El Capitan 10.11 can upgrade Yosemite, Mavericks, Mountain Lion, Lion, or Snow Leopard
- OS X Yosemite 10.10can upgrade Mavericks, Mountain Lion, Lion, or Snow Leopard



