my doubt is this: I developed and published an app on the AppStore (with auto-renwable in-app purchase). A company would like to sell my app to its customers and they ask me if it is possible to have it without going through the store. I thought about the IPA file, downloadable and installable directly from an external site.
is there any way to do it? Preventing expiration messages .. In short, install it completely.
Without jailbreak possibly
You can distribute your app without Apple Store. You will need to enroll for Enterprise Account for this. But you can not use in-app purchase which Apple provides. You will need to use other payment gateways.
Also, the enterprise account certificates have 3 years of validity. More info: https://developer.apple.com/programs/enterprise/