Is supplication after prayer, whether communally or individually, an innovation?

Scholars have differed regarding the meaning of "dubur al-salat" (the end/rear of the prayer) in the Hadith: "O Allah, help me to remember You, to thank You, and to worship You well." The majority of scholars hold that it refers to supplication after the salutation (taslim) of the prayer. However, others, including Ibn Taymiyyah and Ibn al-Qayyim, are of the view that it means supplication before the taslim. They argue that "dubur" is often used to denote a part of a thing, and that the Prophet's actions after the prayer did not include supplication but rather adhkar (remembrances). They also maintain that supplication within an act of worship is better.

Based on this, it is better for a person to supplicate before the taslim. It is permissible for him to supplicate after the prayer, but without making it a regular practice, except after completing the prescribed adhkar. Individual supplication after the prayer is not an innovation (bid'ah), but communal supplication has not been authentically reported from the Prophet (peace be upon him) nor from his Companions.