Staggering Smite
The target takes an extra 4d6 Psychic damage from the attack, and the target must succeed on a Wisdom saving throw or have the Stunned condition until the end of your next turn.
Using a Higher-Level Spell Slot. The extra damage increases by 1d6 for each spell slot level above 4.
Staggering Smite 5.5e 2024 vs. 5e 2014 edition differences
The 2014 version deals psychic damage on hit, imposes disadvantage on attack rolls and ability checks, and prevents reactions until the end of the target's next turn. The 2024 version deals psychic damage, causes the target to be Stunned until the end of your next turn if it fails the save, and increases damage with higher spell slots.