how do I upgrade my 2011 Macbook pro

Please do not hijack other people's threads. Your question is not related to the topic of this thread which is in relation to updating a 2011 iMac. Best for you to create your own thread and provide enough information in it so someone can help you with your specific issue.

That Mac model can't be upgraded past High Sierra.

(186875)

You don’t. High Sierra is as far as a 2011 MacBook Pro can update. It cannot run Mojave, Catalina or Big Sur.

My computer is freezing when I’m trying use serato how do I fix that problem

Nmoodie51 wrote:

My computer is freezing when I’m trying use serato how do I fix that problem

You should start your own post.

Try: https://support.serato.com/hc/en-us