At this point I find iOS 13 to be very stable. I would absolutely recommend it to everyone with at least an iPhone 7.
That’s always frustrating to try to have older versions of software play nice with newer versions of software. I’m curious what Macs you have that can’t be updated to Mohave? Are they older Mac Pros? I wonder if this might be helpful:
Please fully read this first post, you will probably find that you have one or more problems described into the various notes below. Mojave will only install if you have upgraded your BootROM to the current release and your Mac Pro have a Metal capable GPU*. If you are trying to install Mojave...
forums.macrumors.com
• No Mac Pro models.
• Macbook Pro 3,1: Died from NVidia design flaw, triggered by using the machine for gaming and 3D modeling/rendering.
• Macbook Pro 5,5: works fine, but I refuse to use it for anything that will run it hot for extended periods of time because that will probably kill it like its predecessor. Doesn’t officially support High Sierra, but it runs it... No chance of Mojave being installed.
• iMac 12,2: No support of Mojave and no chance of hacking Mojave onto it due to the GPU (and no, I am NOT going to hack a replacement GPU, despite someone showing it’s physically possible - I don’t even want to open that machine again, let alone do THAT much disassembly and hacking).
I have very old Macs because I live in poverty and cannot afford to buy things repeatedly (so, no, I can’t replace my computer every three years to avoid self-destructing machines or planned obsolescence via software upgrades). I also don’t want to buy BOTH a Mac AND a PC (especially when the PC would be for gaming only... though the new Apple Silicon announcement means Bootcamp is dead).
I’ve been waiting over a decade for Apple to sell a desktop/power-user’s machine, not more of these thermally-compromised all-in-ones. If they’d sold a retina display with the 2013 Mac Pro, I’d have bought it. It never came and the third-party displays were reportedly unreliable with the machine (and, in the long term, the machines were reportedly apt to die of thermal stress just like the all-in-ones). It also takes me a lot of time to save money; there’s no way in HELL I could afford a 2019 Mac Plutocrat (plus, the “least expensive” version of the new Mac Pro, the base model, is the most cost-ineffective version).