I can't seem to find explicit mention of this in the release notes, but it appears that support for 32-bit Linux systems has been dropped with the introduction of Bitbucket Server. There are no 32-bit installers available, so far as I can tell.
I currently use Stash on a 32-bit Linux VM system that is perfectly adequate for my needs. Do I now have to create a new 64-bit Linux VM, install 64-bit Bitbucket Server, migrate across all my Stash data, then import it? Sounds like a nightmare... 