Imam Ibn al-ʿArabi, in his Commentary on al-Tirmidhi, after noting the conflicting reports attributed to ʿUmar—and after citing the opinion that the number of rakʿahs for Tarawih has no fixed limit—writes:

“The sound position is that one should pray eleven rakʿahs, for that is how the Prophet—peace and blessings be upon him—performed the prayer and spent the night in worship. Any other number has no basis and no prescribed limit. If a limit must be set, then let it be the limit observed by the Prophet—peace and blessings be upon him. He never exceeded eleven rakʿahs in Ramadan or at any other time. This prayer is the night vigil (qiyam al-layl); therefore it is mandatory to follow the Prophet—peace and blessings be upon him—in it.”

For the same reason, Imam Muḥammad ibn Ismāʿīl al-Ṣanʿānī declared explicitly in Subul al-Salām that performing twenty rakʿahs in Tarawih is an innovation, saying:

“There is nothing praiseworthy in innovation; every innovation is misguidance.” ⦗92⦘