Tex. Estates Code § 403.052

Within six months after the date letters are granted or within four months after the date notice is received under Section 308.053, whichever is later, a creditor with a claim for money secured by property of the estate must give notice to the independent executor of the creditor's election to have the creditor's claim approved as a matured secured claim to be paid in due course of administration. In addition to giving the notice within this period, a creditor whose claim is secured by real property shall record a notice of the creditor's election under this section in the deed records of the county in which the real property is located. If no election to be a matured secured creditor is made, or the election is made, but not within the prescribed period, or is made within the prescribed period but the creditor has a lien against real property and fails to record notice of the claim in the deed records as required within the prescribed period, the claim shall be a preferred debt and lien against the specific property securing the indebtedness and shall be paid according to the terms of the contract that secured the lien, and the claim may not be asserted against other assets of the estate. The independent executor may pay the claim before maturity if it is determined to be in the best interest of the estate to do so.