According to Imaam Abu Hanifa, Witr Salaat is Waajib (compulsory). It is
subordinate to performing Esha Salaat.
Tahajjud Salaat (Salaatul-layl) is Nafl Salaat and may be performed at any
portion of the night. Kindly refer Tahajjud at
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai