The following LaTeX renders just fine with v3:
```tex
\begin{align}
c^2 \amp = a^2+b^2\tag{✶✶}\\
c^2 \amp = a^2+b^2\tag{††}\\
c^2 \amp = a^2+b^2\tag{‡‡}\\
c^2 \amp = a^2+b^2\tag{##}\\
c^2 \amp = a^2+b^2\tag{✠✠}
\end{align}
```
But now in v4 the whole display says "Misplaced '#'". You can see v3 here:
Subsection 7.5: Local Tags on Equations
https://pretextbook.org/examples/sample-article/html/section-mathematics.html#section-mathematics-7
Using \# instead seems to be the solution for v4. (Though with v3, the "\"
renders also.)
Wanted to check that the v3 behavior was perhaps accidental and escaping the
octothorpe is now correct use. Or maybe vice-versa?
Will v4 support the version PreTeXt creates for use with "regular" LaTeX? (I
removed the \label{} from these.) It might be nice if these were identical for
creating both PDF and HTML output (and maybe especially for SRE), and did not
use Unicode characters.
```tex
\begin{align}
c^2 \amp = a^2+b^2\tag{\textasteriskcentered\textasteriskcentered}\\
c^2 \amp = a^2+b^2\tag{\textdagger\textdagger}\\
c^2 \amp = a^2+b^2\tag{\textdaggerdbl\textdaggerdbl}\\
c^2 \amp = a^2+b^2\tag{\#\#}\\
c^2 \amp = a^2+b^2\tag{\maltese\maltese}
\end{align}
Thanks,
Rob