[tex4ht] Subsubsections do not show up in TOC

[Jürgen Hubert]

After I recently updated my LaTeX installation (which I hadn't done for more than a year), I suddenly had the problem that subsubsections no longer show up in the TOC of the EPUB file:

----------

\documentclass[oneside]{scrbook}

\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
%----------------------------------------------------------------------------------------

\begin{document}

This is a test.

\chapter{Chapter Test}

\section{Section Test}

\subsection{Subsection Test}

\subsubsection{SubSubsection Test}

\end{document}

-----------

When I compile this, I get the following messages:

tex4ebook EPUB_V01.tex

[STATUS]  tex4ebook: Conversion started
[STATUS]  tex4ebook: Input file: EPUB_V01.tex
[WARNING] tocid: char-def module not found
[WARNING] tocid: cannot fix section id's
This is pdfTeX, Version 3.141592653-2.6-1.40.24 (MiKTeX 22.1) (preloaded format=latex.fmt)
 restricted \write18 enabled.
entering extended mode
This is pdfTeX, Version 3.141592653-2.6-1.40.24 (MiKTeX 22.1) (preloaded format=latex.fmt)
 restricted \write18 enabled.
entering extended mode
This is pdfTeX, Version 3.141592653-2.6-1.40.24 (MiKTeX 22.1) (preloaded format=latex.fmt)
 restricted \write18 enabled.
entering extended mode
        1 file(s) copied.
        1 file(s) copied.
        1 file(s) copied.
        1 file(s) copied.
HTML Tidy for Windows released on 25 March 2009
        1 file(s) copied.
[STATUS]  tex4ebook: Conversion finished


The end result is that the Chapter, Section, and Subsection show up in the TOC, but the Subsubsection does not. Since I was able to generate files with Subsubsections in the TOC in the past before the update, the logical conclusion seems to be that something went wrong during the update process. And the warnings

[WARNING] tocid: char-def module not found
[WARNING] tocid: cannot fix section id's

are also new.

Now, I was able to find the "char-def" module in a repository,

https://raw.githubusercontent.com/adityam/context-math/master/char-def.lua

I am unsure how to install it so that tex4ebook will find it.

Can anyone give me some advice on how to proceed?

Best regards,

- Jürgen Hubert