So if you updated all your packages in one go and finds that your beamer presentations don’t compile anymore, this is why. Don’t panic though (42), there’s a workaround: put the following line before \documentclass{beamer}:
\makeatletter\let\ifGm@compatii\relax\makeatother
\documentclass{beamer}
\documentclass{beamer}
Read this post for more information.
brilliant, thank you.
Thank you!