Acronym incompatibility hotfix for old TeX versions before 2019

acronym-workaround.tex

% old TeX distributions (<2019) don't contain the capitalization feature yet
% provide a workaround here for the new acronym commands
\usepackage{acronym} % acronyms
\makeatletter
\@ifpackagelater{acronym}{2020/01/01}
{%
% Do nothing for the newer version
}
{%
\renewcommand{\Acl}[1]{\acl{#1}(\textbf{properly capitalized})}
\renewcommand{\Ac}[1]{\ac{#1}(\textbf{properly capitalized})}
\renewcommand{\Acf}[1]{\acf{#1}(\textbf{properly capitalized})}
}%
\makeatother

compiler.log

Undefined control sequence.

The compiler is having trouble understanding a command you have used. Check that the command is spelled correctly. If the command is part of a package, make sure you have included the package in your preamble using \usepackage{...}.

 Learn more
l.94 \Acl
         {ML} has been applied in ...
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.