Development version is the work for next major one (so for the end of the year). On minor version (3.0.2 is a minor version), you will have only bugs fixes of the stable version and minor features adding (if they are not related to a major one added on development version. That’s the only to keep a “stable version”, stable. And next minor version will be out, if we have sufficient bug fixes and adds related to a minor. So impossible to say if we will have another minor one and if yes, when…
You could use master version but It’s recommended to follow what’s added as some major adds could break other things. So sometimes, You have some features that regressed. That how it’s a development version.