glossaries package FAQ
After updating to glossaries v4.50 I'm getting undefined control sequence
The textcase package is obsolete as of 2022 and now simply defines
\MakeLowercase. Therefore the glossaries package, as from version 4.50, no longer automatically loads textcase, unless an old (pre 2.08) version of mfirstuc has been detected. Instead, the glossaries package uses its own
\glsuppercase command for all-caps and mfirstuc's commands for sentence case.
If you want to continue using
\MakeTextUppercase then simply load textcase explicitly.
Alternative link: https://www.dickimaw-books.com/faq.php?itemlabel=undeftextcase
Category: glossaries package
Topic: (La)TeX Errors