Subscriptions that aren’t a Stripe feature

Yes. Core Commerce asks one question of a gateway — does it implement SubscriptionGatewayInterface? — and in practice that has one affirmative answer. Subscribr doesn't use that element or that interface. It asks a smaller question: can this gateway charge a stored token with nobody present? Run php craft subscribr/gateways against your own install and it will tell you before you buy anything.

It still carries subscriptions. The renewal is raised as an incomplete order and the subscriber is emailed a link — incomplete because an incomplete order is a cart, and a cart has getLoadCartUrl(), which drops the subscriber into your own checkout with the renewal already in it. There is no bespoke payment page to build, and nothing to fix when you change gateway.

Yes, in one cart and one checkout. A recurring line is an ordinary line item carrying an option key. Commerce already de-duplicates line items on the purchasable ID plus a hash of their options, so the same product bought once and subscribed to monthly are automatically two separate lines.

Yes — a renewal is a Craft Commerce order. It appears in the order index, in Commerce's reporting, in your order status emails and PDFs, and in whatever other Commerce plugins you run. Your tax rules, shipping methods, discounts and coupons apply to it exactly as they do to any other order, because it goes through Commerce's own recalculation.

Nothing is lost and nobody is double-billed. Renewals more than renewalCatchUpDays (seven by default) past due are abandoned rather than charged, and the skipped cycles are written to the ledger. The next payment date is always computed from the date that was due rather than from now, so a sweep that runs late doesn't walk anybody's billing day forward.

No, and deliberately not. Dunning is in Lite. A store whose cards decline still needs its money, and a store that cancels on the first failed payment is throwing away customers who would happily have paid. Pro adds named sequences, so different plans can be chased differently.

Lite is a complete, working subscription plugin: plans, renewals on any gateway, mixed carts, trials and joining fees, pause, cancel and reinstate, dunning, the subscriber portal, emails, and manual renewal for gateways that can't store a card. Pro adds subscription boxes and build-a-box, skip, swap, prepaid plans, gift subscriptions, plan switching with proration, and named dunning sequences per plan.

The Pro features stop, and they stop honestly. The feature gates read the edition rather than a stored setting, so an install that can no longer edit a Pro configuration doesn't keep obeying one — a box plan whose slots had become unreachable would otherwise ship whatever it liked. The settings screen tells you which of your settings have been suppressed rather than leaving it to a support ticket.

No. Working templates for the whole portal ship with the plugin — copy them into templates/subscribr/portal/ and yours take precedence. craft.subscribr.can(subscription) returns what this subscriber may do right now, with the plan's rules, the edition and the change window already resolved, so a button is never rendered for something the controller would refuse.

Yes, by handle: php craft subscribr/plans/export and php craft subscribr/plans/import. Plans live in the database rather than project config — the same call Commerce makes for its own plans, and for the same reason: a plan can point at a box, and a box points at purchasables whose IDs mean nothing in another environment.