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Is there any way for the general public to get access to Ubuntu pre-release/beta ISOs or tarballs for testing?
I currently help maintain a Linux product, and the bulk of our customers currently use Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. When the next 17.04 and 18.04 LTS releases come out, I would like to be able to test on them before it's released to the general public so that I can confirm that my product works on the latest release. Since I use Gtk and upgrades for it aren't usually backwards compatible (different library version labels), I have to recompile a new version for new distros.
My current issue is that the second a new release of Ubuntu comes out, customers download and install it, test my product on it, then complain that my product is "broken". It would be very helpful to be able to pro-actively handle/test such issues before they arise.
I've gone through the support forums and the testing tracker, but cannot find any info on acquiring/testing pre-releases.