Comment 5 for bug 491165

Until very recently we had a bug that allowed re-uploading of files that had been previously uploaded, which causes havoc across the PPA system particularly when people copy packages around.

We will never allow multiple copies of the same file to co-exist with different contents, it's simply far too confusing for everyone involved.

However, once the file has expired in the librarian, you'll be able to re-upload it. This is a bit of a bug but you can make use of it for now. The real solution is to upload an orig file that's slightly renamed.