My VO2Max has been stuck on one value for 4 months or so, since I don't run outdoors in the winter, and I don't have a power meter on my bicycles.
Yesterday I was bicycling, and I had no change in my VO2Max. I synced with Connect, and it was also showing the same old value.
Today when I woke up, the VO2Max had increased by one, out of the blue. I have done no activities so far today. I synced with Connect, and it now also reflects the increased value.
What is the explanation for this increase in VO2Max? It came from the watch itself (firmware 14.15), not from Connect.