If your computer runs OS X Mavericks or a later version, you are eligible to install macOS Catalina. Additionally, your Mac should have a minimum of 4GB of RAM and at least 12.5GB of free storage space; if you're upgrading from OS X Yosemite or an earlier version, you may need up to 18.5GB of available storage. To ensure you benefit from the latest features while also maintaining your Mac's security, stability, compatibility, and performance, it's essential to keep your software updated. Apple advises users to always use the most recent compatible macOS version for their devices. The earliest macOS version that can be installed on your Mac is the one that originally came with it. For instance, a Mac that shipped with macOS Big Sur will be unable to install macOS Catalina or any earlier versions. If a particular version of macOS is not compatible with your Mac, you will receive a notification from the App Store or the installer, indicating that it is either not suitable for your device or too outdated to be opened on the current macOS version. This ensures users are always aware of their system's compatibility and options for upgrades.