where did the older versions go

Adobe now offers the current and ONE older version via the online program manager
.
I do not know how far back this process will go, but try this link
Direct Download Links https://prodesigntools.com/tag/ddl MAY help
-NOTE that you will have to search the site for your specific download
-you MUST do what it says in Note: Very Important Instructions
-https://prodesigntools.com/adobe-cc-2015-direct-download-links.html#download-instructions
-the prodesign links go directly to Adobe's file server, so this process will
--only work until Adobe completely removes the old version(s) from the server
.
IF/When you do have a download, be sure to copy it to AT LEAST one external device
-since Adobe does sometimes remove old versions from the server
-a usb flash drive or external hard drive, or write to a DVD