Every 4 weeks, just before the Summer season starts the new series, there will be an update for the new series content.

ask me if i feel stupid. . . . :D
since i started playing last in-game winter i didn't know this was a thing. 
thanks bunches

Don't know what keywords to use in google so i game here for help.
so yea as you can see i have there are no rewards nor any challenges, i have also checked the world map and... nothing.
as i can see this also spans over the next 4 seasons.

btw I'm playing on PC
thanks for your time

HELP!