Time Capsule: Options after macOS support ends

The part that is deprecated is Apple File Protocol (AFP) -- not to be confused with DISK formats: Apple File System (APFS) or older MacOS Extended aka Hierarchical File System Extended (HFS+).

Apple File Protocol (AFP) is a Server protocol that Apple has been trying to retire for a long time. Server Message Block (SMB) has proved more suitable, and SMB has taken its place for Server traffic.

What keeps working:

• use of the Time Capsule as a Router remains, but the limited protocols and Wi-Fi capabilities it supports are getting really old. It might be a good time to consider the more advanced capabilities of a more modern Router as your Main Router, and turn the Time capsule into a repeater/extender by turning off its ability to dispense local IP addresses using DHCP. Apple calls this 'Bridge mode' but that terminology is far from standard.

• the drive that contains your accumulated backups is likely fine, and could be moved, unchanged, to an external USB enclosure and connected:

-- to ONE Mac on your network, for locally-attached backup.

-- to a different Mac on your network, running 10.13 High Sierra or higher, to use as a Shared Time Machine destination. [10.13 is the oldest MacOS that supported the ability to properly specify where the shared backup destination was located and what access was allowed by which Macs) on your network.]

It is also possible, but not guaranteed to work:

-- to the USB port of a Router that supports Time Machine features, elaborated below.

-- to a Network Attached Storage (NAS) device, elaborated below

But again, this might be a good time to ADD and additional Time Machine drive, as step toward modernizing your backups for future needs. When you ADD a Time Machine destination drive, its starts a new stand-alone backup staring with today. Every-other backup goes to every-other drive until you decide to remove one. This means at no time are you left 'working without a net'.

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Upgrades to consider:

You can also move that drive or a different drive and connect it to:

• the USB port on a modern Router -OR-

• a Network Attached Storage (NAS) device, which tends to be a simple, network-attached computer with good I/O capabilities, typically running Linux.

... PROVIDED that Router or NAS (which I am calling the Host system) supports the ability to create and maintain a 'sparse bundle disk image file'. That is an entire Virtual Disk inside an expandable file on the Host system. Using a 'sparse bundle disk image file' launders out the details of exactly how that Host system stores its files.

A 'sparse bundle disk image file' is exactly what you will see at top-level on the Time capsule drive if you were to go and inspect it manually. Keep in mind to look inside that Virtual Drive, it takes several Minutes to Mount that disk image file to use it.

Time Capsule will no longer work starting with macOS 27. It uses a deprecated format for networking (AFP), and while that format works with macOS 26 Tahoe, the format will no longer be supported by Apple starting with macOS 27. It has been over 7 years since the Time Capsule was last sold by Apple, and that means the product is now considered 'obsolete'.

The simplest method to continue using Apple’s Time Machine to back up your Mac(s) is to buy an external drive and connect it to the Mac(s) regularly to back them up (or leave the drive connected to a desktop Mac). External storage is relatively inexpensive, a 1 TB SSD or a 2-4 TB HDD can be purchased for <$100. 

To back up your Macs over WiFi, the most straightforward way is to use a network attached storage (NAS) device – essentially a box for hard disks that connects to your network. Ideally, choose one that offers turnkey support for Time Machine out of the box, both Synology (setup instructions) and QNAP (setup instructions) do so. Technically, you can stand up a Time Machine server in other ways (including using a Mac as a TM server), but an NAS is arguably the most straightforward way to set up network Time Machine backups. 

Personally, I use a Synology DS223j with a pair of 10 TB HDDs installed to back up 5 Macs in the house with Time Machine (separate shared folder for each Mac sized at ~2.5x the internal storage), with the remaining space used as general file storage for everyone in the house. 

One other important note for macOS Tahoe or later::

If you re-initialize the Drive in the Time Capsule, you are DONE using that drive inside the Time Capsule.

You will NOT be able to create any new backups on the Time Capsule drive after that.

When you install the next MAJOR upgrade, MacOS 27, it is expected that you will not be able to do ANY backups or RESTORES using that Time Capsule directly, under any circumstances.

It is warning you to take action now, or you will be left without direct access to your backups in the near future.

And if you ERASE that drive NOW, under MacOS 26 Tahoe, you can NOT create a new backup on it while still inside the Time capsule.

How come I have had that messages you cant use TM anymore for over six months and it says latest OS each time and I can still do backups? I must have a donut and apple breakfast

So why is this message going on each time and I can still use TM