[SOLVED] Downgrade to dev-Release not in apt-cache anymore (?)

Hi, can someone help me to fix my broken dev-system. did a huge mistake by believing that after waiting a few weeks dev would be on track again, at least not for me. so i stop trying arround and would like to go back to 1512 which worked great. BUT its not in apt-cache anymore. how can i go back to a release that seems to not be cached anymore?

Happy for any help!!! thanks Norbert

fixed it easily as old versions installed are located in:

Back on track with #1512 and memo to myself to not update until 2.5 is stable hopefully.