Fix problem with changes and xcolor packages.

ifiseries.sty

@@ -121,7 +121,10 @@
 \RequirePackage[\ifiseries@inputencOptions]{inputenc}
 \RequirePackage[T1]{fontenc}
 \ififiseries@xcolor
-\@ifclassloaded{beamer}{}{\@ifclassloaded{dinbrief}{}{\RequirePackage[rgb,svgnames]{xcolor}}}
+% The changes package will load xcolor, which clashes with the beamer and dinbrief classes.
+% We thus refrain from loading both if one of those classes is active, and simply load the changes package
+% which loads xcolor if everything is alright.
+\@ifclassloaded{beamer}{}{\@ifclassloaded{dinbrief}{}{\RequirePackage[xcolor={rgb,svgnames}]{changes}}}
 \fi
 \RequirePackage[\ifiseries@babelOptions]{babel}
 
@@ -266,7 +269,6 @@
 \RequirePackage{placeins}
 \RequirePackage[draft]{fixme}
 \fxsetup{theme=color}
-\RequirePackage{changes}
 \normalem
 
 \ExplSyntaxOn