When authoring a gem, what would be reccomended practice for version restrictions of dependencies. For example I know that know that my gem works wih rubyzip version 2.x, but I also know that it works for 1.9 as well. Should I state
spec.add_runtime_dependency 'rubyzip', '>1.8'
or if the rubyzip version 1.9 is long time outdated, it is more common to "push" change for 2.x line? Also if I use the mentioned line, that I risk incompability with future versions, but on the other hand, leave the coice to the user.
Note: the questions is generall and dependency on rubyzip is just an example.
If you know that your gem works with rubyzip 1.9, then there's really no need to force people to use >=2.0 with it.
Sure, updating dependencies would be a good idea for your library-user to do, but it's not your job to be the "update-your-software-police"!
Specifying that the version must be < 3 is generally advisable (although not consistently done by developers), as there's a reasonable risk that a major dependency version bump will be incompatible with this version of your code.
So, as a compromise, you could do:
spec.add_runtime_dependency 'rubyzip', '>=1.9', '<3'
See the documentation for valid syntax examples.