Digambar Jains observe Diwali as Mahavira’s Nirvana. The main puja and lighting of lamps are typically done on Kartik Amavasya night, after sunset. Many sanghs perform the ritual during the twilight hours (Pradosh kaal) or even up to Nishita (midnight). Exact timings can vary by local panchang and temple notices, but the central idea is to light lamps to dispel spiritual darkness and remember Mahavira’s teachings. Digambar and Śvetāmbara traditions may have small calendar differences in the date, but the practice of lighting lamps on this night remains the same. For 2025, Kartik Amavasya is commonly observed on October 20, with the Amavasya period sometimes extending into October 21, so many communities mark the main Diwali observance on the night of Oct 20. You can read more here and here