apple watch software 2.1 and says software is up to date

Hi

First update your iPhone to the latest compatible software version:

Update the iOS on your iPhone, iPad, or iPod touch - Apple Support

Then follow the remaining steps to update your Apple Watch:

Update your Apple Watch - Apple Support

Apple Watch Series 2 models can be updated to watchOS 4.x if the paired iPhone is an iPhone 5s or newer model that has first been updated to the latest version of iOS 11.x

If you instead have an iPhone 5 or 5c, then your devices cannot be updated beyond iOS 10.x and watchOS 3.x.

If you are unable to install the update, then it may help to follow the steps in the second article under the headings "If you need help updating" and/or "If you installed an iOS or watchOS beta or developer seed" as appropriate.

No, there is no other option.

If your friend's iPhone gets warmer than expected, then I suggest that they contact Apple Support (remote diagnostics and/or mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider for assistance:

Keeping iPhone, iPad, and iPod touch within acceptable operating temperatures - Apple Support

Keep in mind that, immediately after performing an iOS update, your iPhone may perform background tasks, such as when apps re-index or re-analyse data.

In order to pair your Apple Watch with your iPhone 6s, start by updating your iPhone 6s to the latest version of iOS 11.x.

Follow the instructions in my previous reply, including to pair and update the Apple Watch afterwards.

As I hoped to explain in my previous replies, it is normal not to be able to pair your Apple Watch to your iPhone 6s - including updating the software on your watch, which will take place during the set up process - until your iPhone 6s has first been updated to the latest version of iOS 11.x

I'm afraid that I can't say why your Apple Watch was no longer paired with your iPhone.

More information:

If your Apple Watch isn't connected or paired with your iPhone - Apple Support