Are the occurrences on Friday – such as the two adhans, praying two or four rak'ahs before Jumu'ah and the like afterwards, the Imam raising his hands in supplication and wiping his face, and the congregants following him – considered innovations? And what should one do if they are an innovation? Is the Imam's collective supplication after the prayer permissible?

The Prophet used to go out on Fridays and ascend the minbar, then the muezzin would give the adhan, and then he would deliver the sermon. There was no sunnah before the Jumu'ah prayer during his time. For this reason, the majority of imams hold that there is no specific sunnah prayer before Jumu'ah, and nothing has been authentically reported from the Prophet regarding it, neither in word nor deed. The prayer before Jumu'ah is an innovation of later generations. There should be a sufficient period between the first and second adhan for Jumu'ah.

Reciting du'a in unison aloud behind the imam after the prayer is an innovation. What is prescribed is to remember Allah aloud with the remembrances reported from the Prophet.

Regarding prayer after Jumu'ah: The Prophet used to pray two rak'ahs in his home, and he commanded those who prayed it to pray four. Ibn Taymiyyah said: If one prays in the mosque, one prays four; if one prays in his home, one prays two.

Wiping the face after du'a has no authentic hadith to support it, and some scholars have explicitly stated it is an innovation.