Short answer: Yes.

In Shwetambar tradition, doing tivihar at night (no food after sunset, but water is allowed) does not prevent you from keeping upvas the next day.

Practical points (Shwetambar):

• Upvas starts with pachchakkhan (vow) in the morning, before you eat anything.
• During upvas, only boiled and cooled water is taken in prescribed timings; no food.
• After sunset, keep chauvihar (no food and no water) to complete the upvas well.
• If you already ate solid food that morning, that day cannot be counted as upvas; you may opt for another tapa like ayambil instead.

Tradition note:

• Shwetambar upvas typically allows boiled water in the day.
• Digambar practice is generally stricter (often no water at all for upvas). This is just for understanding the difference; follow your Shwetambar sangh’s guidance.

If possible, take pachchakkhan from a guru or in front of the sthapana during pratikraman.