Whether you use a SAT solver or not doesn't really matter for the purposes of this discussion -- the SAT solver is just a tool that can be used to find a soluti

Whether you use a SAT solver or not doesn't really matter for the purposes of this discussion -- the SAT solver is just a tool that can be used to find a solution given a set of logical statements. My point really was this: both a maximal and minimal version can exist that satisfy a minimum-version (<=) bound dependency. In such case, which one is chosen is a matter of policy, not correctness. As for not allowing a newer package to be published with a lower version number, that is sometimes necessary in a back-publishing scenario. For example, imagine that you publish a newer package with a higher version that has breaking changes and a security fix, and you also publish a newer package of an older version that just has the security fix. It's entirely valid to do so, for what should be obvious reasons.