What is the ruling on omitting the final Tashahhud and the prayer upon the Prophet (peace be upon him) in Tarawih prayer?

Reciting the final Tashahhud and sending blessings upon the Prophet (peace and blessings be upon him) are considered pillars of prayer by the Hanbalis and Shafi'is. For those who omit them in Tarawih prayer, their prayer is invalid according to some scholars, and there is no difference between obligatory and supererogatory prayers in this ruling, because what invalidates an obligatory prayer also invalidates a supererogatory prayer. As for the view of scholars who do not consider the final Tashahhud and sending blessings upon the Prophet therein to be pillars, the prayer is valid.