I just updated to latest TL on one of my Linux VBox to test it.

A file which compiles OK on my other TL 2024, now no longer compiles using tex4ht on this new Linux with the updated TL 2024.

Here is MWE

------------------
\documentclass[12pt]{book}%
\usepackage{fancybox,fancyvrb,xcolor}

\ifdefined\HCode % tex4ht
\DefineVerbatimEnvironment{X301}{Verbatim}
\else
\DefineVerbatimEnvironment{X301}{Verbatim}{samepage,fontsize=\small}
\fi

\begin{document}

\begin{X301}
Out[30]= TransferFunctionModel[{
{{5(1 + s)(2 + s)}},
s(4 + s)(6 + s)}, s]
\end{X301}

\end{document}
--------------------------------

make4ht -ulm default -a debug A.tex 'mathjax,htm'

Gives

------------------------------
LaTeX Font Info: Trying to load font information for T1+lmtt on input line 1
2.

(/usr/local/texlive/2024/texmf-dist/tex/latex/lm/t1lmtt.fd
File: t1lmtt.fd 2015/05/01 v1.6.1 Font defs for Latin Modern
)
! Undefined control sequence.
<argument> \FancyVerbBackgroundColor

l.12 \begin{X301}
----------------------------

Attached is the log file A.log

This file compiles with no problem using lualatex on this updated TL.

This file also compiles with no error on my other Vbox with Linux which uses the original TL 2024 which I have not updated.