Is it obligatory for the middle tashahhud in prayer to be recited in its entirety, without the supplication, and for the supplication to be only after the final tashahhud?

Scholars differed regarding reciting the complete Tashahhud in the middle sitting. Some permitted invoking blessings upon the Prophet (peace be upon him) therein, citing the generality of hadiths as evidence, while others stated that only the Tashahhud should be recited. Ibn Mas'ud (may Allah be pleased with him) described the Prophet's prayer (peace be upon him) saying: "Then, if he was in the middle of the prayer, he would rise when he finished his Tashahhud, and if he was at the end of it, he would supplicate after his Tashahhud with whatever he wished to supplicate, then he would say the salam." Ibn al-Qayyim said: "He (the Prophet) used to make this Tashahhud very brief," and it was not narrated that he (peace be upon him) invoked blessings upon himself and his family in the first Tashahhud. Therefore, the Sunnah is to limit oneself to the Tashahhud only in the middle Tashahhud, and if one invokes blessings upon the Prophet (peace be upon him), it is permissible, but it is preferable to omit it.