What is the ruling of Islamic law regarding phone alerts during congregational prayer, despite the Imam's reminder to turn them off before the prayer begins?

Previous fatwas have stated that it is disliked to carry anything that distracts a worshipper from attaining khushu' (devotion) in prayer. Worshippers should be mindful of this and advise their brethren who continue to practice it, as this cooperation is a form of cooperation in righteousness and piety.