Hello Zepphead2016,
Thanks for using Apple Support Communities.
I see that you have updated the software on your iPhone 6S and you are still receiving an out of date software message when trying to pair with your Apple Watch. I know how important it is to make sure that you can set up and pair your Apple Watch. I have something that I would like you to try.
Use Update the software on your Apple Watch and make sure that your Watch also has the latest software installed, specifically, this section:
To update the software on your Apple Watch, you need to:
- Connect your Apple Watch to power, and keep it on the charger until the update is complete.
- On your iPhone, open the Watch app, tap the My Watch tab, then tap General > Software Update.
![User uploaded file](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/applewatch/iphone6-watchos2-watch_app-general-software_update.jpg)
- If asked for your iPhone passcode or Apple Watch passcode, enter the passcode.
- Wait for the progress bar to appear and complete. Don't restart your Apple Watch during the update, which might take some time. When the update finishes, your Apple Watch will restart on its own.
![User uploaded file](https://support.apple.com/library/content/dam/edam/applecare/images/en_US/applewatch/iphone6-watchos2-watch_app-general-software_update-downloading.jpg)
Once you've confirmed that both devices have the latest software installed, use the following resource and try to set up and pair your Apple Watch again:
Set up your Apple Watch
Have a great day!