It's a 2014 model, it can definitely run Macos 11. But as it has been unused for the past few years, it hasn't been upgraded and it's quite funny how utterly unusable it became: very few websites work at all (certificates problem), it's impossible to install any current application because even Firefox LTS requires 10.13 or so, and it's impossible to upgrade without using another Mac to download the update tool. That's not very user-friendly if you ask me :)
