Texas Civil Practice and Remedies Code - CIV PRAC & REM § 16.070. Contractual Limitations Period

(a) Except as provided by Subsection (b), a person may not enter a stipulation, contract, or agreement that purports to limit the time in which to bring suit on the stipulation, contract, or agreement to a period shorter than two years.  A stipulation, contract, or agreement that establishes a limitations period that is shorter than two years is void in this state.

(b) This section does not apply to a stipulation, contract, or agreement relating to the sale or purchase of a business entity if a party to the stipulation, contract, or agreement pays or receives or is obligated to pay or entitled to receive consideration under the stipulation, contract, or agreement having an aggregate value of not less than $500,000.