Here is a simple, traditional way to handle Upvas that starts at 12 midnight, with note on differences between Digambar and Śwetambar.

• When to open (end the Upvas)

- Most common approach: finish the vow after you have completed the prescribed hours and after you have done a short prayer/reflective practice (often a Pratikraman or Samayik) for the day. In many communities, this means opening at or after sunrise the next day, not exactly at midnight. If your tradition specifies a 24-hour Upvas from 12:00 AM to 12:00 AM, you would end the vow at the end of that 24-hour period and then perform Pratikraman and Navkar to mark the completion. - If your local tradition follows sunrise-to-sunrise (common in many Śwetambar households), you would open after the sunrise of the new day, following your morning prayers.

• What to chant/recite when you open

- Navkar Mantra (Namokar Mantra): recite it with proper devotion. - Arti or Manglik prayers as per your tradition (Śwetambar families often do a shortarti or Mangala-charitra after breaking the fast). - A short Pratikraman (confession and reflection) for the day, or a Samayik (self-imposed time of meditation/condensed reflection) if you normally observe one on Upvas days. - If you do Sravak (household lay practitioner) rites, you may recite a short Stavan or Stuti that aligns with your sect’s practice.

• Important notes

- There are differences between Digambar and Śwetambar practices. Some Digambar households emphasize more austere, short prayers upon opening; Śwetambar practices may include a wider set of daily prayers and a slightly longer closing ritual. If you have a guru or family tradition, follow that precisely. - Keep the opening simple and focused on gratitude, self-discipline, and non-violence (ahimsa).

If you’d like, I can point you to a page on JainKnowledge.com with a short, sect-appropriate outline for ending Upvas.