# Cannot use \usepackage with custom document class “ws-srl”

I am having problems with \usepackage using a custom document class. An error was returned whenever \usepackage was used. Please help me.

\documentclass{ws-srl}
\usepackage{caption}

\begin{document}


The error returned is:

 "! LaTeX Error: \RequirePackage or \LoadClass in Options Section.See the LaTeX manual or LaTeX Companion for explanation.Type H <return> for immediate help...."


I added \usepackage{caption} in the class file. But it returned another error

 "! LaTeX Error: Command \captionbox already defined.Or name \end... illegal, see p.192 of the manual.See the LaTeX manual or LaTeX Companion for explanation.Type H <return> for immediate help.... ...ption@withoptargs{\caption@ibox\@gobble}}"


The class file and tex file can be found in the following link

Tex and class file

The complete folder is given below

Tex folder

• Welcome to TeX.SX! I don't get the first error, only the second one; from what I can see, the class is not compatible with the caption package: it happens for several custom classes. This one is particularly nasty, I'm afraid. Use it only if you're really forced to. – egreg Nov 4 '15 at 8:09
• I fear, the class file is too old and too unmaintained. – user31729 Nov 4 '15 at 8:14
• @egreg Do you want to take any action here? – Johannes_B Aug 6 '16 at 16:11
• @Johannes_B Answered – egreg Aug 6 '16 at 19:56

The second error is raised because the caption package is not compatible with the ws-srl class. It's a class designed for submissions to World Scientific publications and they decide the format.