diff --git a/doc/manual/R-defs.texi b/doc/manual/R-defs.texi
index 6d52bac..23002ba 100644
--- a/doc/manual/R-defs.texi
+++ b/doc/manual/R-defs.texi
@@ -1,5 +1,5 @@
 @documentlanguage en
-@documentencoding ISO-8859-1
+@documentencoding UTF-8
 
 @macro R{}
 R