Which of these two is the version mentioned in Hadith? And what is the status of its chain?
1) Whoever prays the dawn prayer (Fajr) in congregation is under the protection of Allah for that day.
2) Whoever prays the dawn prayer (Fajr) is under the protection of Allah for that day.
These are two separate Hadiths that are reported by several Sahabah (radiyallahu’anhum) with slight variants in the wording.
1) The first one is reported by Sayyiduna Abu Bakrah (radiyallahu’anhu) in Musnad Bazzar, Hadith: 3616 and Al-Mu’jamul Kabir.
‘Allamah Haythami (rahimahullah) has declared the narrators of Tabarani as authentic (rijalus sahih). Majma’uz Zawaid, vol. 1 pg. 296. Also see Targhib, Hadith: 647.
2) The second version is reported by Sayyiduna Jundub ibn ‘Abdillah (radiyallahu’anhu) in Sahih Muslim, Hadith: 1491, Sayyiduna Abu Bakr (radiyallahu’anhu) in Sunan ibn Majah, Hadith: 3945, Sayyiduna Tariq ibn Ashyam (radiyallahu’anhu) in Al-Mu’jamul Kabir, Hadith: 8188, and ‘Abdullah ibn ‘Umar (radiyallahu’anhu) in Musnad Ahmad, vol. 2 pg. 111 and Musnad Bazzar, Hadith: 5988.
Also see Targhib, Hadith: 643, 644 & 648.
Imam Muslim (rahimahullah) has cited this Hadith in the midst of other Hadiths that encourage Fajar Salah [and the other Salahs] in congregation. Therefore ‘Allamah Nawawi (rahimahullah) worded the chapter for this Hadith as: ‘The chapter of the virtue of ‘Isha and Fajr Salah in congregation’.
Also see Al-Mufhim, Hadith: 542.
And Allah Ta’ala Knows best.