Is breaking the fast obligatory, and should a Muslim break their fast before catching the Maghrib prayer in congregation, or should they pray first and then break their fast?

The Sunnah (definition) is to hasten the breaking of the fast, based on the Prophet's (peace be upon him) saying: "The people will continue to be upon goodness as long as they hasten the breaking of the fast." This is done by eating a few mouthfuls to quell the hunger, then performing the prayer, and then returning to the food. This was the practice of the Prophet (peace be upon him); he would break his fast with fresh dates before the prayer, and if not available, then dried dates, and if not, then sips of water.