From: [email protected] As for reason why old one is not removed, it is because Debian keeps not just newly installed kernel, but also one previously installed. One before that was removed by apt-get autoremove.
Unless different desktops have different autoremove behavior in my recent experience kernels can only be removed manually. If you get a current today's image of 8.8 and update/upgrade, then switch to testing and upd/upg, then unstable and upd/upg and autoremove as many times as you like, you will end up with 3 kernels as a choice to boot unstable from. I think in the past it did not work this way.
