I was looking for an older version of our genome assembly in Ensembl Metazoa and I thought there was an archive of older releases as for the main site. But I am unable to find it. Did I overlook something? IF there wasn't any, that make things rather complicated for looking up old gene and transcript ids.
To add to tothepoint's answer, all Ensembl Metazoa releases are archived on the FTP site: http://ftp.ensemblgenomes.org/pub/metazoa/
We only maintain web archives for specific releases (listed in tothepoint's answer)
I apologize for my confusion, I have found the archive. (Sometimes, scrolling down helps, must have panicked, too). Thank you very much. I have edited the question title to avoid creating a wrong impression.