I have added a sprite actor in a matinee sequence where I change it’s location with a Movement track. I also want to change its transparency and I remember seeing a screenshot with a Sprite Color track added, but there’s no such option, at least not any more.
I found out that it’s the LinearColor property track that works for sprite color. HOWEVER, it doesn’t allow me to alter the alpha value, only RGB, so I took a different approach: I converted the sprite actor to a blueprint, added an exposed float variable attached only to the alpha value of the sprite color and added a float property track to animate it.