2020 Janmashtami ISKCON
Krishna Janmashtmi is recorded two days back to back. Janmashtmi ISKCON is one of them. ISCKON stands for International Society for Krishna Consciousness & was founded on the principles of Vaishnava traditions and most followers of the ISKCON are the followers of Vaishnavism. No grains are supposed to be consumed while fasting on Janmashtami until the next day when the fast is broken. Parana which implies breaking the fast ought to be done at a suitable time.
For Krishna Janmashtami fasting, Parana is done next day after sunrise when Ashtami Tithi and Rohini Nakshatra are over.
See also: Nakshatra Calculate
If Ashtami Tithi and Rohini Nakshatra don't get over before sunset then the fast can be broken during the day when either Ashtami Tithi and Rohini Nakshatra is over. At a point when neither Ashtami Tithi nor Rohini Nakshatra is over before sunset or even Hindu Midnight (otherwise called Nishita Time), one should be waiting to get them over before breaking the fast.