A:
witr in Ramadan after Tarawih (special supererogatory night Prayer in Ramadan) is performed in congregation. We do not know of any evidence indicating the permissibility of offering Witr regularly in congregation at any time other than Ramadan. However, if Witr is sometimes performed in congregation, this is permissible, as this was done by
Ibn `Abbas with the Prophet (peace be upon him), and
Abu Al-Darda' did it with
Salman. As to the preference of congregational over individual Salah, this is related to the Faridah (obligatory) Salah, as the Prophet (peace be upon him) said,
"Salah performed by men in a congregation is twenty-seven degrees better than Salah performed individually."
(Agreed upon by Al-Bukhari and Muslim)
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.