If a message like "It may have been corrupted or tampered with during downloading” occurs when trying to install older versions of Mac OS X, it might be that the installer is too old and the certificate has expired.
To fix this, set the date and time the install is being done to some time a few years in the past (about the time the installer would have been current). Set it using the date command from terminal: date {month}{day}{hour}{minute}{year} (example date 010101002015 for 1 am on 1 Jan 2015) then install again.
I usually write a blog post about once a week. The latest post can be viewed here: We Need Trump and Musk: I wonder if Trump and Musk might like to visit here after they have finished sorting out America! (posted 2025-02-11 at 11:40:37). I do podcasts too!. You can listen to my latest podcast, here: OJB's Podcast 2025-01-30 Pragmatic Libertarianism: Freedom is important. Maybe it's all that really matters..