Is persevering in supplication (Du'a) after Witr, just before Fajr, an innovation (Bid'ah)?

Persevering in supplication after Witr and before Fajr is among the best deeds. The Prophet, peace and blessings be upon him, encouraged supplication at this time, which is when the Lord, Almighty and Exalted, descends to the lowest heaven. During this time, Allah the Almighty praised His servants who seek forgiveness in the pre-dawn hours.