I have version 26.2.2 (57373), the update check 'does not see' version 26.3.0. The message appears that there are no updates.
Hello @AndreaB22 , The update is being released gradually, which may be why it is not yet appearing on your side. However, Parallels Desktop 26.3.0 is available on our website. Please download and install the Parallels Desktop 26 for Mac Image from the Parallels website. Alternatively, you may use this direct download link.