How can I securely use old Apple devices with outdated software?

Recycle all of it.

Better to have the materials reclaimed and reused than to let these devices languish unused.

Wipe the devices properly and drop them at your local Apple Store, OfficeMax, Staples or other local recycler. The old and obsolete devices will never meet the standards of security of the modern internet and putting them into the hands of someone who needs a computer would breed frustration and anger when they cannot perform adequately.

Recycling is the best path, imho.

Please see: What to do before you sell, give away, trade in, or recycle your Mac - Apple Support

And if you recycle, then you don't have to reinstall the OS. Just make sure you've wiped your data and disassociated them from your Apple Account (Apple ID).

Depends on what you do and what you might use them for. Options for the Macs are:

• install server software and use one for backups;
• install Linux on one and play around with it to add a string to your bow - I've done this with an old MBA to manage backups between two NAS boxes;
• use one as a streaming service around your home network for music and movies;
• call round the local schools and see if they can use them for comp sci or something.

The iPads and iPhones are less useful, but I use an old SE as an iPod. I've deleted everything off it that I can, I don't sycnch it with the cloud and it's just full of music and I leave it plugged into the car.

neilfrommd wrote:

i have a growing collection of old Apple devices. The hardware is perfectly functioning but the software is no longer updated…and the usual wisdom is that it is no longer secure.

Whose wisdom might that be?