${?}_{is\text{a}\text{c}\text{h}\text{a}\text{n}\text{g}\text{e}\text{b}\text{a}\text{s}\text{e}\text{d}on\text{i}\text{n}\text{c}\text{r}\text{e}\text{m}\text{e}\text{n}\text{t}\text{a}\text{l}\text{i}\text{m}\text{p}\text{r}\text{o}\text{v}\text{e}\text{m}\text{e}\text{n}\text{t}\text{s}to\text{a}\text{d}\text{o}\text{m}\text{i}\text{n}\text{a}\text{n}\text{t}technological}$

design such that the improved technology $is$ fully backward compatible with the older

technology