I have an Imac late 2013 Catalina MacOS 10.15.7. Is there any way to upgrade what I have

No. Catalina is the last compatible operating system for your Late 2013 iMac and Apple no longer supports it with security and browser updates. You can use it until it fails at some future point, and by installing the current Firefox or Brave browser versions to keep your Internet connections secure (e.g. banking, etc.).

If you're referring to the OS, no.

If you're referring to a newer computer, buy one normally.

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