<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_1_1455951477341_4904" dir="ltr">If I remember well, there is (was ?) some kind of objective for backward compatibility, namely that all (updates of) versions of all TeX engines should produce the exact same output for a given input file. The background being that any TeX file that used to compile correctly in the past should also compile correctly in the future.</div><div id="yui_3_16_0_1_1455951477341_4905" dir="ltr"><br></div><div id="yui_3_16_0_1_1455951477341_4972" dir="ltr">Is my memory correct? And just out of curiosity, does the rule apply to the DVI / XDV file? WIth pdflatex, I guess there is no DVI file to compare.</div><div id="yui_3_16_0_1_1455951477341_4973" dir="ltr"><br></div><div id="yui_3_16_0_1_1455951477341_4974" dir="ltr">Cheers,</div><div id="yui_3_16_0_1_1455951477341_6926" dir="ltr">Wilfred</div><div id="yui_3_16_0_1_1455951477341_6927" dir="ltr"><br></div><div id="yui_3_16_0_1_1455951477341_4880"><span></span></div> <div class="qtdSeparateBR"><br><br></div><div style="display: block;" class="yahoo_quoted"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Saturday, February 20, 2016 2:15 PM, Akira Kakuto <kakuto@fuk.kindai.ac.jp> wrote:<br></font></div> <blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; margin-top: 5px; padding-left: 5px;"> <br><br> <div class="y_msg_container">> Why is it so? And what generates this difference? The question has been<br clear="none">> lingering on SX for a while<br clear="none">> <a shape="rect" href="http://tex.stackexchange.com/questions/292675/why-does-xelatex-produce-different-files-from-the-same-deterministic-sources" target="_blank">http://tex.stackexchange.com/questions/292675/why-does-xelatex-produce-different-files-from-the-same-deterministic-sources</a><br clear="none">> but with no reasonable answer!<br clear="none"><br clear="none">I wrote a possible answer on SX.<br clear="none"><br clear="none">Best,<br clear="none">Akira<div class="yqt5816593881" id="yqtfd72631"><br clear="none"><br clear="none"><br clear="none"><br clear="none">--------------------------------------------------<br clear="none">Subscriptions, Archive, and List information, etc.:<br clear="none"> <a shape="rect" href="http://tug.org/mailman/listinfo/xetex" target="_blank">http://tug.org/mailman/listinfo/xetex</a><br clear="none"></div><br><br></div> </blockquote> </div> </div> </div></div></body></html>