如果我理解最新的 latex 更新，您不需要再声明 textcomp 就可以使用它的符号。我发现其中一些符号在更新的 latex 下会产生错误。这是一个最小示例：
\documentclass[letterpaper]{article}
\usepackage[T1]{fontenc}
\usepackage{textcomp}[=2018/08/11]
\begin{document}
Use of {\textmu} to Minimize Worker{s\textquotesingle} Risk of Musculoskeletal Injury.
\end{document}
它与 rollback 命令（第三行）配合得很好。如果我删除它，日志文件中会出现以下错误：
! Undefined control sequence.
l.5 Use of {\textmu
} to Minimize Worker{s\textquotesingle} Risk of Musculosk...
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.
! Undefined control sequence.
l.5 ...extmu} to Minimize Worker{s\textquotesingle
} Risk of Musculoskeletal ...
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.
有什么指导吗？这是错误还是我在这里做错了什么？