diff --git a/README.md b/README.md
index 7346033..40e64cb 100644
--- a/README.md
+++ b/README.md
@@ -97,12 +97,14 @@ Building from source
   * the [Protocol Buffers][] library and compiler
   * [Boost][]
   * `ncurses`
-  * `libutempter`
   * `zlib`
   * the Perl module [IO::Pty][]
 
   including development packages where applicable.
 
+  If `libutempter` is available, `mosh-server` will record sessions in the
+  `utmp` file, which makes them visible to commands like `who`.
+
   The file `debian/control` contains a list of the relevant Debian packages.
 
   [GNU Autotools]:    http://www.gnu.org/software/autoconf/