Before the new Succession Amendment (Intestacy) Act (2009), a person leaving a valid will would have their assets distributed according to the Probate and Administration Act of 1898. This act has stood for over 100 years.
The most striking change in the new act is that the spouse of the deceased has a greater entitlement. Interestingly the new act contemplates the deceased having multiple spouses, all of which are entitled to a share.