Pros of any versioning scheme:<br><ul><li>Allows clients to avoid updating when the API changes.</li><li>Reduces the cost of making breaking changes.<br></li></ul>Cons of any versioning scheme:<br><ul><li>Requires the code to accumulate more and more &quot;if version &lt; foo&quot; cases, which must be tested, reviewed for security, and updated as things in core change.</li>
<li>Can&#39;t entirely prevent breaking things. For example, the introduction of ContentHandler removed sectioning for Javascript and CSS pages, and there&#39;s no sane way to preserve that in an old API version.<br></li>
</ul>Please expand these lists.<br>