# Microtype package produces warning when using LuaTex

I am receiving the following warning message whenever I include microtype:

Module microtype Warning: overwriting function keepligature' on input line 59


Here is a minimum working example:

\documentclass{article}
\usepackage{microtype}
\begin{document}
Test
\end{document}


I do not get the error when I use XeLaTex.

Does anyone know why microtype is giving this warning?

If it is harmless, is there any way to suppress it?

• – Thérèse Mar 8 at 2:59
• @Thérèse I have seen that bug, but I do not think it is related. I am using the latest version of microtype that has fixed this problem. – Andy N Mar 8 at 4:42
• That's an info message not an error and it is harmless. – Ulrike Fischer Mar 8 at 8:06

## 1 Answer

You get the warning as the newest luaotfload version changed the handling of ligatures in letterspaced fonts and for this predefines the keepligature function (see the luaotfload documentation for details).

microtype has its own keepligature definition and when installing it now warns that it overwrites luaotfload` definition.

The microtype definition is compatible with the luaotfload definition -- at least the tests didn't reveal any problem --, so the warning can be ignored (but it can't be silenced).