In a document using lipics-v2016.cls, the spacing of labels in the appendix bibliography is broken. Presumably the problem is that the tweak on \@biblabel implemented near the end of apxproof.sty (namely, \def\@biblabel{\hspace*{-2em}\small\@oldbiblabel}%) should also be applied to this document even though it uses lipics-v2016.cls and not lipics.cls.
I would suggest changing the test \ifthenelse{\equal{\@currentclass}{lipics}}{ to a less restrictive condition, maybe testing if the class starts with "lipics" (e.g., with xstring's \IfBeginWith). Maybe there are better options, e.g., testing if a lipics-specific command is defined...
In a document using lipics-v2016.cls, the spacing of labels in the appendix bibliography is broken. Presumably the problem is that the tweak on
\@biblabelimplemented near the end of apxproof.sty (namely,\def\@biblabel{\hspace*{-2em}\small\@oldbiblabel}%) should also be applied to this document even though it uses lipics-v2016.cls and not lipics.cls.I would suggest changing the test
\ifthenelse{\equal{\@currentclass}{lipics}}{to a less restrictive condition, maybe testing if the class starts with "lipics" (e.g., with xstring's\IfBeginWith). Maybe there are better options, e.g., testing if a lipics-specific command is defined...