Blur

Level & School
2nd-level illusion
Casting Time
Action
Range
Self
Components
V
Duration
Concentration, up to 1 minute
Classes
Sorcerer, Wizard

Your body becomes blurred. For the duration, any creature has Disadvantage on attack rolls against you. An attacker is immune to this effect if it perceives you with Blindsight or Truesight.

Level & School
2nd-level illusion
Casting Time
Action
Range
Self
Components
V
Duration
Concentration, 1 minute
Classes
Sorcerer, Wizard

Your body becomes blurred, shifting and wavering to all who can see you. For the duration, any creature has disadvantage on attack rolls against you. An attacker is immune to this effect if it doesn't rely on sight, as with blindsight, or can see through illusions, as with truesight.

Blur 5.5e 2024 vs. 5e 2014 edition differences

The 2024 version specifies "up to 1 minute" duration, while the 2014 version states "1 minute" (no mechanical difference). The 2024 version explicitly states "any creature has Disadvantage" and clarifies immunity if the attacker perceives you with Blindsight or Truesight, but these are clarifications, not mechanical changes.