SDCL § 5-9-29: Tax purchaser's rights under installment contract--Payment of delinquent installments.

The purchaser of any such land sold for delinquent taxes shall acquire only such rights and interests as belong to the party holding the contract of sale hereinbefore provided for, and the right to be substituted as the assignee thereof and upon exhibition to the proper officer of the tax certificate given at a tax sale, in case the land has not been redeemed, such tax purchaser shall have the right to make any payment of principal or interest then in default upon the contract of sale, as the assignee thereof, prior to the redemption of such land.