I saw a vivosmart 5 brochure which says it can measure stairs climbed. But I can't see that on the watch or the app. Works with my Fenix. So is that due to an error in the brochure or the current software update allows it to?

Surprise! They removed the barometer. It was in the Vivosmart 4 and now not in the Vivosmart 5. Watch upgrade from 4 to 5 with features removed.

Forget about a software update, it would require hardware.

So give less, advertise falsely and charge more!!??

Yes, look at the Garmin site under Vivosmart 5 and see the Specs. That brochure is not correct.