Can I update the hardware on my 2013 iMac to support Sequoia?

You cannot update the hardware on your 2013 iMac to support Sequoia. It is forever limited to Catalina.

I really love all the ports. I wish they'd bring them back!

You didn't say which of the 2013 iMac models you have, but they seem to have shared these features:

• Four USB-A (USB 3.0) ports
• Two Thunderbolt 1 (up to 10 Gbps) ports with MiniDisplayPort connectors that doubled as Mini DisplayPorts
• 3.5mm analog/optical combo output jack
• SDXC slot
• 10/100/1000 BASE-T Ethernet
• Support for a single external Mini DisplayPort display, or two external Thunderbolt Display, with resolutions of 2560x1600 pixels maximum.

None had Firewire - Apple having dropped that the previous year when iMacs got really thin.

These days, all Macs except for the MacBook Neo come with multi-purpose USB-C ports that support

• USB 3.* (up to 10 Gbps)
• USB4 (20 Gbps and 40 Gbps)
• DisplayPort
• Thunderbolt 3, 4, or 5 (up to 40 Gbps for Thunderbolt 3 or 4; more than that for Thunderbolt 5)

While many Macs lack built-in SDXC card readers, USB card readers are not expensive or hard to find.

lulajean wrote:

I really love all the ports. I wish they'd bring them back!

As you're now aware, you cannot update your hardware except by buying newer.

Your 2013 iMac has these ports:

• Four USB 3 - (up to 5 Gbps)

• Two Thunderbolt 1 - (up to 10 Gbps)

iMac (21.5-inch, Late 2013) - Tech Specs - Apple Support

The current iMac (exc the lowest tier) has this:

Four Thunderbolt 4 ports with support for:

• Thunderbolt 4 (up to 40Gb/s)
• USB 4 (up to 40Gb/s)
• USB 3.1 Gen 2 (up to 10Gb/s)
• DisplayPort

iMac - iMac Technical Specifications - Apple

So, as you can see, it's not just about the number of ports, it's also about the speed and versatility of the ports available in the newest Macs. And docks/hubs that add capability - SD card reader, HDMI and Ethernet - are inexpensive to add.

And the only way to use any OS newer than Catalina is by replacing your hardware rather than updating it, which you now know is not possible.

It's high time to make plans to replace that hardware. Your old iMac wants to retire and you should let it. 🙂

macOS 10.15 Catalina is the highest you can go

but you can have a Security Update 2026-001 from Feb 2026.

lulajean wrote:

Can I update the hardware on my 2013 iMac to support Sequoia?

I really love all the ports. I wish they'd bring them back!

No.

macOS Sequoia is compatible with these computers - Apple Support

Here is the current Mac desktop lineup, rated from best to worst in terms of expansion ports.

• Mac Studio with M5 Max or M5 Ultra chip
• Mac mini with M6 or M5 Pro chip
• 24" M4 iMac – variant with four Thunderbolt ports
• 24" M4 iMac – variant with two Thunderbolt ports

All of these Mac minis and Studios have two front-panel USB-C ports. These don't support USB4, DisplayPort, or Thunderbolt (unless you have a Mac Studio with an Ultra chip), but even just having two front-panel USB-C ports which support USB 2/3 can be very convenient. (Especially if you keep a couple of USB-C to USB adapters handy for use when needed.)

The iMacs have no front-panel ports, which makes it much less convenient to temporarily plug in backup drives, USB flash drives, and other accessories unless you have a dock or hub. The two-Thunderbolt-variant of the iMac would not be the one you would want to get. It is so short on ports that you would need a dock or hub right away.

lulajean wrote:

I really love all the ports. I wish they'd bring them back!

if you need lots of ports (on a newer Mac), look for a Thunderbolt dock with whatever combination of ports you prefer.

Or for the BYOD (Bring Your Own Display) crowd:

Hardware prices have been heading upward though, so whether you buy now, buy later for more, or wait and buy after (if?) the bubble bursteth?