Both traditions accept the same basic Jain fact:

• Bhagwan Parshvanath’s Janma Kalyanak tithi (birth kalyanak) is Pausha Krishna Dashami (10th day of the dark half of Paush).

Then why do Digambar and Shvetambar often keep different dates in the English (Gregorian) calendar?

1. Different Panchang / calculation methods

• Each sampradāy generally follows its own traditional Jain Panchang (calendar).
• The same lunar tithi (Pausha Krishna Dashami) can fall on slightly different civil dates depending on:

- Which Panchang you use (Digambar vs Shvetambar traditions, or even regional variants), - Rules like sunrise‑based tithi, local longitude/latitude, etc.

• So:

- Tithi is same → Pausha Krishna Dashami. - Observed English date can differ → e.g., one calendar may show 6 January, another 7 January for the same tithi.

2. Regional & historical practice

• Over time, different Jain centers (cities, countries) adopted slightly different panchangs.
• These patterns became “our tradition” in that area:

- Some Shvetambar sanghs follow one printed calendar, - Some Digambar sanghs another, - Even within a sect, two regions may be a day apart.

So the difference is not in belief about Parshvanath Bhagwan, but only in how the lunar tithi is converted to the modern date.

3. What you can practically do

• For bhakti and sādhanā, the inner feeling is more important than the exact English date.
• Follow:

- The Jain calendar/Panchang used by your own guru / sangh / temple, and - Keep Pausha Krishna Dashami for Parshvanath Janma Kalyanak with shraddhā, vrat, svādhyāy and Navkār bhakti.

You can see a simple explanation about Parshvanath Janma Kalyanak here