Is it permissible to say the Taslim in the Shafa and Witr prayer after saying "Ashhadu An La Ilaha Illa Allah Wa Anna Muhammadan Rasoolullah"?

The scholars differed regarding the ruling on sending blessings upon the Prophet, peace and blessings be upon him, in the last tashahhud (definition). The Shafi'is and their followers, and those who agreed with them, held that it is a pillar ( rukn) without which the prayer becomes invalid, citing as evidence the hadith (definition) of Ka'b ibn Ujrah regarding how to send blessings upon the Prophet in prayer. The Hanafis and Malikis, however, held that it is recommended (mustahabb) and not obligatory. The more preponderant opinion is the first one. Therefore, whoever prays two rak'ahs or prays witr with one rak'ah must send blessings upon the Prophet, otherwise their prayer will be invalid. It is also recommended to send blessings upon the family (al) and then supplicate with whatever one wishes.