iMacs have always had upgradeable RAM, just about the only user-serviceable part in them. There's a little door you can open on the back by the power connector.

iMacs have always had upgradeable RAM, just about the only user-serviceable part in them. There's a little door you can open on the back by the power connector. https://support.apple.com/en-us/HT201191 https://support.apple.com/en-us/HT201191