The Messenger of Allah ﷺ used to perform witr with seven or five rakahs, without separating them with a salam or any speech.
حدثنا أبو بكر بن أبي شيبة حدثنا حميد بن عبد الرحمن عن زهير عن منصور عن الحكم عن مقسم
كان رسول الله ﷺ يوتر بسبع أو بخمس لا يفصل بينهن بتسليم ولا كلام
Graded sahih. Nasai reported it, 3/239, Book of Night Prayer, Chapter on How to Perform Witr with Five Rakahs and Mention of the Disagreement Concerning Hakam in the Hadith on Witr, no. 1715, 1716, from the hadith of Mansur, by this chain.Hakam bin Utayba sometimes practiced tadlis and narrated with an ambiguous form of transmission. Tabarani reported it, 23/378, no. 895, from him, from Miqsam, from Ibn Abbas, from Umm Salama, by this chain. Hakam has another route in Nasai, no. 1717, and this hadith has corroborating narrations that support its meaning.