Apple Magic Keyboar/Magic Mouse and Mac Mini late 2012

Every upgrade puts a device further away from the original OS, iPhones, Minis etc. and a device never works as well as it did with the original OS.

That said, if you do not need to use older (often free) 32 bit programs, installing an SSD (i.e. 128 or 256gb) only for the OS and programs would make up for some of the lack of processing power in your 8 year old Mini. You can leave the HD in place and clone the OS and programs to the SSD, then install a newer OS on top of it. Then use the old internal HD only for your personal files/storage.

I bought a 2013 MacBook w/SSD w/ 10.14 - it was fast, but even faster when I downgraded to OS 10.12

I have El Capitan on a 2012 and use the Magic 2 KB and Magic Mouse 1 fine. The KB can be used with or w/o cable. I can not advise for the v1 KB or the v2 Mouse but do know that the Mouse cable is for charging only.

I seem to remember that the Magic KB/Mouse worked with Mavericks 10.9 and Yosemite 10.10 also.

If you have El Capitan 10.11 or Sierra 10.12, I would NOT upgrade to HIgh Sierra 10.13

If you do your 32 bit programs will likely NOT work and the machine (designed for much older OS) will not be as fast.

El Capitan can be downloaded and IMO is a perfect OS for an 8 year old Mac.

Hello,

As long as your Macintosh is running macOS 10.13 High Sierra or later then your Mac can use Magic Mouse (1st and 2nd generation) and Magic Trackpad (1st and 2nd generation).

I like the MM1 (2 AA batts) as the MM2 when it goes dead you can not use until charged as the recharge plug fits in the bottom.