Chanukah always falls on the 25th of Kislev and, in the West, Christmas falls on 25 December. The two festivals often overlap, but rarely coincide. This year, however, Chanukah starts on 25th December. The kids are off school in Israel. Although additional Songs of Praise are added to synagogue services, Chanukah is more of a nationalistic than a religious festival. Despite dating back to Second Temple times, and preceding Christmas by a couple of centuries, it is a relatively late addition to the Jewish calendar and commemorates events that took place after the Biblical period.
Work is not prohibited. Consequently, the Israel Patent Office will be open as usual and deadlines falling over Chanukah will be observed. Note, in Israel, Sunday is a working day, and the weekend is Friday-Saturday.