THEOS might be a contender. I don’t know when it was created, but I ran into a user 15 years ago. They were old then and still providing active support to custo

THEOS might be a contender. I don’t know when it was created, but I ran into a user 15 years ago. They were old then and still providing active support to customers. http://www.theos-software.com/ http://www.theos-software.com/ Edit: Looks like it died in 2014 or 2016 or, at least, that’s the latest update I see. Update: Yup, it’s now listed as suspended. Looks like it was started in 1983.