Just to pitch in a bit here are my thoughts. I personally use semVer to version my package mostly for the clear information about breaking changes. This also means that you will have to bump the major when support for a Umbraco version has to be dropped. For the problem of supporting multiple versions that may occur in this case i think you can follow the LTS/edge version thinking; so that you keep a major version of your package supporting the Umbraco LTS version and then all new majors untill the next major only the newest major will be supported. With this tactic you will only have to support 2 major versions of your packages and you can keep making breaking changes to improve the package between LTSs. So for an example v1-3 could support Umbraco v9/10, v4 support Umbraco v11 5-6 support Umbraco v12. You can think of it like having a LTS and a bleeding edge track for your packages. This also allows devs to pick how often they would like to update a package/solution.If this works in practice is yet to bee seen from my side but it's my current plan.