In all cases where the penal sum of any bond becomes insufficient, the principal shall either give a strengthening bond with the same surety to attain a sufficient penal sum, or give a new bond to cover the entire liability. Strengthening bonds will not be approved where any notation is made thereon which is intended, or which may be construed, as a release of any former bond, or as limiting the amount of any bond to less than its full penal sum. Strengthening bonds shall show the current date of execution and the effective date.

(72 Stat. 1352, 1394; 26 U.S.C. 5175, 5551)