What car can you take a picture of for the August contest

They said it on Forza hub what I read is that you had to use the Porsche 718 boxster, but that was for August 1st Thru the 4th now what car can you use from August 5th Thru the 10th August 11th Thru the 17th August 18th Thru the 24th and August 25th to the 31st in Forza 6 it does not tell me know where what I can use it says I can’t use the Porsche that it contest is over can someone please help me with this issue thank you