I had heard about software 4.10 for the Fenix 6 yesterday. I was, at that point, still at 3.80. Late last night, i.e., Friday, September 27, 2019, I connected the Fenix 6 to Garmin Express. Got the update pretty quickly. Took a few minutes to install, but there were no problems. Pretty smooth.
As you can see from the above descriptions, which I got from ‘Garmin Forums’, they essentially track each other. That is good — albeit with the newer Fenix 6 leading the way and the MARQ getting the features added on. But, not an issue. Garmin is doing the MARQ updates quickly. Hope it carries on like that.
The only new enhancement that really interested me was the ‘all day respiration’ widget. I installed it on both watches. Neat. I even read how it works — by minutely analysing changes in heart rate at the millisecond level. It is good to have a widget that tells you that you are still breathing! At my age that can be an issue. I like the readings I am seeing. They look OK to I, but I have no idea if they are accurate.