Isn't it available here?

https://www.jetbrains.com/idea/download/other/#releases-2012

Interesting. On https://account.jetbrains.com/licenses/assets I have a "Download" button and "Download a code for offline activation" and "Generate legacy license key" buttons.. I figured I could use one of those if I ever decide to cancel my sub, but I admit I have not tested the theory. It's possible your copy is indeed too old.

FWIW, I dont think I use any software (unless it is single, narrow purpose) that is almost 1.5 decades old. Fun fact, docker was released in 2013, so your IDE likely doesn't even support build targets in containers.

But if you have the receipt, email the company and ask for help obtaining an old version. They are very willing to help customers, both current and previous.