I've been using the HRM-Run v1 that came with my 620 with my 935 w/o issue. (Black snap-off module w/ a runner). I just ordered a 945 since it doesn't look like a 955 is happening this year. I only use the strap when running. I don't swim or cycle as a sport. Can I stick w/ my old HRM-Run or do the current HRM-Run or HRM-Pro to collect additional data?
Yes, it is compatible. I use the same version. If the HRM-Run v1 is on SW 6.60, you will have all 6 running dynamics data like with the new red HRM-Run.
You can check the SW version on the watch sensor menu at status. The 945 will not automatically update the sensor SW. If it is older, there is workaround to do the uptate.
Yes it is compatilble , I was using it before it broke and I switched to the new HRM-run
