(a) A surety company may be relieved of its obligations under a surety bond executed on behalf of a county depository after the 30th day after the date it gives written notice to the commissioners court requesting to be released.
(b) A surety company is not relieved under Subsection (a) of liability for a loss sustained by the county before the expiration of the bond.

(c) If a depository’s surety company requests to be relieved from its obligations under Subsection (a), the depository shall provide further security acceptable to the commissioners court to secure county funds under this chapter. The depository shall provide the further security before termination of the surety’s obligations under the bond. The new security shall be filed in the county clerk’s office.