Board Thread:Game Discussion/@comment-26502662-20150616155457/@comment-25956839-20150702174559

I don't know for sure, but there is a pattern to challenges being added to the series. Look at the the special events at the bottom of Races and Price Special Events and compare how many have been added to the Race Series

The previous release added two of the three Ferrari events to the series, see Race Series, you can see Redline Origins and MotorFiesta 1 have been added as special events, the third one Scuderia Ferrari Championship was re-released Scuderia Ferrari Championship/New, maybe that will be added in the future. These where originally released Dec 2014, so have taken 5~6 months to be added to the race series.

My best guess is The 500 will be the one of the next ones to be added to the series, maybe in a month or two.