Tex. Est. Code § 255.351
A testator may not exercise a power of appointment through a residuary clause in the testator's will or through a will providing for general disposition of all of the testator's property unless:
Added by Acts 2009, 81st Leg., R.S., Ch. 680 (H.B. 2502), Sec. 1, eff. January 1, 2014.