Software or a feature that still works but may be removed and no longer works is considered deprecated. You should avoid using deprecated software or features to reduce or eliminate the need to update or change features later.
For example, the <font> tag is a deprecated feature of HTML (hypertext markup language) and should be avoided when changing the font style on a web page. While it may still work currently, when later removed from HTML programming, you would need to update your web page and use a different, non-deprecated HTML tag to change the font style.
Typically, when something becomes deprecated, it's because there is a better solution. In the case of our above HTML example, many HTML tags and attributes are deprecated because they're now done using CSS (cascading style sheets).