It hasn't been anounced yet. I can't remember when it usually is announced, I never keep track of the exact time. But I assume it should come in the next month or two, if not sooner.
If you want to learn more about Super Sentai, these sites might help ( some might not be fully updated).
http://supersentai.com
http://sentaispoilers.com
http://rovang.org ( there is a Super Sentai site linked to on the index)
You could also do a search on Wikipedia for Super Sentai.