All of the currently released Solidus versions still support Rails 5.1.x, and I think it's important to try to continue to support it as long as possible in this extension in particular.

Many Solidus extensions rely on solidus_support v 0.5 and greater, and at the moment our store cannot get any of the latest commits from solidus_tax_cloud or solidus_handling_fees or solidus_stripe or solidus_related_products or . . . you get the idea . . . until we transition our application to Rails 5.2. (This is a huge undertaking, because it means somehow getting away from the deprecated solidus_active_shipping!)

Because this extension is so widely used (indeed that's the whole idea!), I believe it is important to have compatibility requirements that are as loose as possible, otherwise any requirements here will constrain the entire ecosystem of a user's Solidus extensions.

I'm not familiar with what if anything changed in activesupport from v5.1 to 5.2, but all of the specs are green and, as I say, all current versions of Solidus support 5.1 so I think we should endeavor to continue to do so until there is a convincing reason otherwise!