Minimal versions put the burden of background compatibility on the maintainer of the dependency. If such is the case, library maintainers are constrained to refrain from breaking background compatibility at minor version changes, like Go itself does. In this case, you can merge, resolve the conflict by incrementing the dependency's version number, rebuild and retest and if all goes well commit. With lockfiles if branch X requires 1.4, branch Y requires 1.5 and 1.5 breaks 1.4, good luck with that. You'll need to update branch X to support 1.5.