diff --git a/src/couch_log.erl b/src/couch_log.erl
index dbc8cad..826f009 100644
--- a/src/couch_log.erl
+++ b/src/couch_log.erl
@@ -26,6 +26,7 @@
 -callback error(Fmt::string(), Args::list()) -> ok.
 -callback critical(Fmt::string(), Args::list()) -> ok.
 -callback alert(Fmt::string(), Args::list()) -> ok.
+-callback emergency(Fmt::string(), Args::list()) -> ok.
 -callback set_level(Level::atom()) -> ok.