btrieve is committed to backward compatibility, as versions of btrieve until version 6.15 use a standard file format and, until btrieve 6.0 was released, were completely backwards compatible. btrieve 6.0 introduced new features and had to break compatibility with older versions of the software to implement more advanced features. the api likewise remained backwards compatible, with only one feature (split files to separate media) being dropped. at one point, btrieve's former ceo ron harris stated that "the version 1.0 api is still supported in version 6.15, and we're going to keep it forever!" ("kyle", pg 11).