Only releases get tested

Only proper releases get tested for real. You can beg users to try pre releases or beta packages, but only once you actually release a "stable" release you will get the extent of the testing that you want and need. That includes if you for example mark something deprecated or obsoleted it does not matter at all even if they remain so for an extended period of time as it will only be truly effective when you ship the first release with the change and then people will react (and some will yell at you).