Installing old versions of InDesign

yes, all cc versions are available (with subscriptions).  only the 2 most recent are available via the cc desktop app, but all are available.

after cc 2019, you must contact adobe support*.

cc 2019 and prior are available from prodesigntools.com. https://prodesigntools.com/adobe-direct-download-links.html

follow the directions (esp, step 1)

save the install file. it may not remain online.

thank jim @ prodesigntools.com

*use a browser that allows popups and cookies and contact adobe support by clicking here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human

p.s you can also use phone (but chat is usually quicker), https://helpx.adobe.com/contact/phone.html

p.p.s. you can also use twitter to tweet @AdobeCare

p.p.p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true

You can use the link @Eugene Tyson shared, the downloads are done from Adobe servers so it's safe. What you should do is try the link and see if you can download the installer(it won't work if Adobe shutdown the servers serving the installers). Once you get the installer test and if it installs properly then you can go ahead and purchase a subscription.

Do note that even if all things work you are still using an unsupported version and don't expect any bug fixes or support from Adobe for this version.

-Manan

I don't think you can go back to 2018.

Max previous versions is 2

You can find those here

https://prodesigntools.com/adobe-cc-2019-direct-download-links.html#:~:text=Down%C2%ADload-,InDesign%20CC%202019,-(64%2Dbit)

You have to install Adobe Creative Cloud to manage your subscription and software installs/updates.

You can install older versions

But you will not be able to update to the latest version until you update your OS. I have the same restrictions on a couple of old Macs.

The main downside I experience is when I receive InDesign files created using a newer version than mine.