Short answer:

• In Jainism, Diwali is the Nirvana (moksha) day of Lord Mahavira. It is observed on Kartik Amavasya. The next day is commonly celebrated as the Jain New Year with Gautam Swami attaining keval jnana. The core meaning is the light of true knowledge, not fireworks. For 2025, the main Diwali day is October 20, 2025 (Kartik Amavasya), though some local panchangs may vary by a day.

What to do (simple, traditional practice):

• Pray to Mahavira, recite simple prayers, and read or listen to Uttaradhyayan Sutra.
• Light a lamp (diya) to symbolize the light of knowledge.
• Observe a calm, sattvik day; many families perform a short prayer, a swadhyay, or a small samayik/pratikraman.
• Do not celebrate with loud firecrackers; ahimsa is central.

Traditions in Digambar vs. Śvētāmbar:

• Both traditions commemorate Mahavira’s Nirvana on Diwali and Gautam Swami’s Kevala Jnana the following day. There may be small differences in calendar calculations or ritual details, but the spiritual purpose remains the same.

Related overview you can read:

• Diwali (Jain Dharma) in 2025: main day October 20, 2025; Amavasya timings can vary by region.
• Mahavir Nirvana Kalyanak (Diwali) overview and its significance.