Not quite true!<p>A good faith effort was made for compatibility.  But it was not perfect. Hence <a href="http:&#x2F;&#x2F;www.perl.com&#x2F;doc&#x2F;FMTEYEWTK&#x2F;perl425.html" rel="nofollow">http:&#x2F;&#x2F;www.perl.com&#x2F;doc&#x2F;FMTEYEWTK&#x2F;perl425.html</a> was created to let people know where the problems were.