Agreements concerning succession.

(1) No agreement to make a will, to give a devise, not to revoke a will, not to revoke a devise, not to make a will, or not to make a devise shall be binding or enforceable unless the agreement is in writing and signed by the agreeing party in the presence of two attesting witnesses. Such an agreement executed by a nonresident of Florida, either before or after this law takes effect, is valid in this state if valid when executed under the laws of the state or country where the agreement was executed, whether or not the agreeing party is a Florida resident at the time of death.

(2) The execution of a joint will or mutual wills neither creates a presumption of a contract to make a will nor creates a presumption of a contract not to revoke the will or wills.