As everyone knows the Xbox one does not currently have an adapter for using older headsets. So what can we do. We can make one out of the existing headset supplied with the system.

I tested it with Astro A40's and it works great

A bit of extra info

How hard is this to do?
If you can solder this is pretty simple. If you can't, well it's still simple.

**********For those who originally tied the black and bare wire, please desolder the black wire and tape it up. It should not be used in this configuration. It's providing 1V and I was essentially shorting it to ground, which caused my battery to drain rather fast.

thanks to turbotboz for this info.

Step 1: Items Needed

Here's what you need

- Official Xbox One Headset
- 2.5mm Stereo Inline Jack (Mode Electronics 24-271-1 or similar) It cost about $2 from my local electronics parts store
- Soldering Iron
- Solder
- Torx T5 or T6 screwdriver depending on headset. Some were installed with T5 and others T6
- Hot Glue Gun (optional)

Step 2: Headset Teardown

Technically you can just cut the wire and solder it to the connector but I wanted to keep the strain relief that was part of the wire
You can follow the pictures, they should be in order
1) Remove the foam from the earpiece (it's like a sock that slips over the earpiece)
2) Remove the 3 T6 screws from the earpiece and pull off the black plastic piece that the screws were holding
3) Remove the heat shrink that is on the exposed bare wire, and the heat shrink in the white wire
4) Carefully desolder the blue, black, white and bare wire.
5) Remove the 4 T6 screws holding the green plastic piece, and remove the green plastic piece.
6) Gently Pull/Pry the strain relief/wire out of the headset (this may take a bit of pressure, also if you are prying it be careful not to cut through the strain relief).
7) Done go take a break

Step 3: Soldering the Connector

So the headset has 4 wires, Blue, Black, White, and bare

Blue - speaker Left
Black - speaker Right
White - Microphone positive
Bare - Ground

The connector should have 3 solder points, ground, left and right channel.

Imagine the diagram below is the connector split in half,
                       ___________________________
                     | | | |_______________________
                      |________|_________|_________|                                                     /
Jack Opening__________________________ Wire To headset Controller/
                      | Ground | Speaker L |  Mic + |_____________________/
                      |________|_________|_________|

1) Remove the sheath from the connector
2) Run the wires through the sheath
3) Carefully solder the wires to the proper part of the connector (see attached image)
4) Carefully twist the sheath on
5) Push the wires strain relief so that it's about half way into the sheath

You're done