In Jain practice, fasting rules vary by the type of vow (vrat) and by local tradition, so you’ll see different ways people break their fast.

• Common approach: many upvas (fast-for-a-day) are observed from daylight to daylight. If you begin the fast after sunset, some people break it after dawn, and some break at sunrise. The key idea is to keep the cycle clean and to end the fast with the new day.
• Why some break at sunrise: breaking at sunrise aligns with the start of the new day and helps maintain discipline by not eating through the night. It also reflects the practice of starting the day with purity and gratitude.
• Why some break after sunset: some communities observe a day-long fast starting after the previous sunset and ending after the next sunset or after the first light of morning, depending on the exact vow. For those who started after sunset, breaking after night ends (dawn) is a natural way to complete the cycle.
• Digambar vs. Shvetambar differences: there can be differences in details of how meals are taken, how strictly night-time eating is avoided, and which foods are permitted during a fast. These are traditional variations rather than contradictions, and your specific practice is best guided by your guru or local temple.

In short: you can break after sunrise or dawn if your vow was to fast daylight-plus-after-sunset; the important part is following the exact rule you’ve taken and keeping the intention of ahimsa and self-discipline. If you’re unsure, ask your guru or a knowledgeable elder in your community for the precise guidance for your specific fast.