这个 MWE 触发了字体警告，我很确定 1 月份没有发生过这种警告：
\documentclass{bmcart}
\begin{document}
\begin{frontmatter}
\dochead{Document}
\end{frontmatter}
\end{document}
bmcart.cls从那以后我就没再做过任何改变（版本控制2014/01/24），所以我认为这是由于其他包或 LaTeX 二进制文件的变化造成的（我在 Windows 10 上使用的是最新的 MiKTeX）：
LaTeX Font Info: Checking defaults for OML/cmm/m/it on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for T1/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for OT1/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for OMS/cmsy/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for OMX/cmex/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
LaTeX Font Info: Checking defaults for U/cmr/m/n on input line 2.
LaTeX Font Info: ... okay on input line 2.
("C:\Users\xxx\AppData\Local\Programs\MiKTeX 2.9\tex/context/base/mkii\supp-pdf.mkii"
...
LaTeX Font Warning: Font shape `OT1/cmss/bx/n' in size <13> not available
(Font) size <12> substituted on input line 4.
...
LaTeX Font Warning: Font shape `OT1/cmss/m/it' in size <8> not available
(Font) Font shape `OT1/cmss/m/sl' tried instead on input line 6.
...
LaTeX Font Warning: Size substitutions with differences
(Font) up to 1.0pt have occurred.
我可以/应该做什么更好/不同的事情？
（通过视觉比较，我没有看到新旧文档之间的区别。这可能只是关于之前被抑制的警告？）