\ProcessKeysPackageOptions{} seems to be obsolete

[svenp09]

The used \ProcessKeysPackageOptions{} seems to be obsolete.

[ExpPhysU]

Minimal failing TeX-file

\documentclass[]{scrbook}

\usepackage{chemformula}

\begin{document}

Hallo

\end{document}

[ortrs]

I ran into this same problem after I updated via MikTex (I am not sure what version was there before, it says it was packed on "01/24/2022". From the latex documentation: https://tex.stackexchange.com/questions/648584/as-of-2022-how-should-one-build-class-package-options-without-l3keys2e

By changing line 481 in chemformula.sty:

\ProcessKeysPackageOptions{chemformula/load-time}

to:

\ProcessKeyOptions [chemformula/load-time]

This works with the latest MikTex update on my system.

[josephwright]

See #21 or one could use a conditional - I went for the low-hanging approach