How about finding some old android phones and running Engine Driver? Steve updates it regularly and is open to suggestions. I don't use it often, but I like working with someone who cares about users and the way they use the app.
I already have couple of old "burner-phone" Android ones wunning Engine Driver.
I'm not and Apple fan. My real phone is a Motorola freebie I got frm my service provided.
My friend had "his and hers" iPhone S phones he hasn't been using for years and instead of trashing them (recycling) he gave them to me. They are in like-new condition (always were in phone protectors). The batteries in them were very weak, so I bought couple of new batteries and replaced them. Now these phones are fully functional WiFi devices, so I really want to get the WiThrottle to work on them. These are really nice phones (you know, Apple makes really good stuff).
That's why I'm trying my best to make them useful and great again.
The WiThrottle developer was a nice guy and tried to help me, but maybe it is Apple themselves who are controlling the older app version availability. I just thought he has some back door to supply me the app installation file and a way to upload it to the phone.