My company distributes an app on the regular AppStore. Some customers host the backend on-premises and are not updating the backend as often as we update the app. We've told our customers that if they don't follow the backend upgrade, they should use an MDM software to manage the installation/update of the app on the phones of their employees.
We're supposed to deliver critical/security fixes to the older version of the app. So for example, the latest app on the store is v2.0.0, a customer has v1.2.0 and we make a security patch on v1.2.1.
We can't distribute v1.2.1 and v2.0.0 to the store at the same time, nor can we just send an IPA build from Bitrise.
We do not build ad-hoc apps (but we could, if that's the way to go) and we (currently) don't have Apple Business Manager.
Is there a step by step guide for folks like me who have not come in contact with "alternative" forms of app distribution? Thanks!