diff --git a/apps/emqx_bridge_rabbitmq/rebar.config b/apps/emqx_bridge_rabbitmq/rebar.config
index a2f072e48..a6af22040 100644
--- a/apps/emqx_bridge_rabbitmq/rebar.config
+++ b/apps/emqx_bridge_rabbitmq/rebar.config
@@ -1,6 +1,6 @@
 %% -*- mode: erlang; -*-
 
-{erl_opts, [debug_info]}.
+{erl_opts, [debug_info, {feature, maybe_expr, enable}]}.
 {deps, [
     %% The following two are dependencies of rabbit_common
     {thoas, {git, "https://github.com/emqx/thoas.git", {tag, "v1.0.0"}}},
diff --git a/bin/emqx b/bin/emqx
index bd51106ca..3ee57288f 100755
--- a/bin/emqx
+++ b/bin/emqx
@@ -1188,10 +1188,10 @@ case "${COMMAND}" in
         esac
         case "$COMMAND" in
             foreground)
-                FOREGROUNDOPTIONS="-noshell -noinput +Bd"
+                FOREGROUNDOPTIONS="-enable-feature maybe_expr -noshell -noinput +Bd"
                 ;;
             *)
-                FOREGROUNDOPTIONS=''
+                FOREGROUNDOPTIONS='-enable-feature maybe_expr'
                 ;;
         esac
 
diff --git a/build b/build
index 4a5e01f7e..7c74e5d90 100755
--- a/build
+++ b/build
@@ -136,7 +136,7 @@ make_docs() {
     local docdir="_build/docgen/$PROFILE"
     mkdir -p "$docdir"
     # shellcheck disable=SC2086
-    erl -noshell -eval \
+    erl -enable-feature maybe_expr -noshell -eval \
         "ok = emqx_conf:dump_schema('$docdir', $SCHEMA_MODULE), \
          halt(0)."
     local desc="$docdir/desc.en.hocon"