Unless you have a specific reason for version 2.00, use the latest official firmware (6.61) for better compatibility and security. You can get it directly from Sony's servers by searching "PSP 6.61 firmware download".
Sony pushed its last PS Vita system software (3.74) in May 2021. No new updates are expected. However, the term is often searched by users who mistakenly believe a new firmware has been released. In reality, “new” refers to: