ANSWER:

Saying the Athkar in congregation is an innovation.

Saying it individual but loudly is an issue of dispute. Our scholars say that this is sunnah as per the hadeeth of Ibn Abbas. Other scholars say that the sunnah is to say it silently such as sheikh Al Albani.

Either way, he is not committing any innovation. 

Sheikh I have prayed behind imams who make their adhkaar loud after the prayer,,,is it recommend or it’s an innovation,??

Prayer | November 1, 2018 2:34 am
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Since it is good to send to do durood before and after prayer,can i do such while in sujood if i want to pray and before teslim?