diff --git a/index.js b/index.js
index aa08106..1b018b1 100644
--- a/index.js
+++ b/index.js
@@ -37,7 +37,13 @@ module.exports = (headers) => {
     if ('return-path' in headers && headers['return-path'] === '<>') {
         return true;
     }
-    if (headers['preference'] === 'auto_reply' || headers['preference'] === 'bulk' || headers['x-preference'] === 'auto_reply' || 'x-autorespond' in headers) {
+    if ('preference' in headers && headers['preference'].toLowerCase() === 'auto_reply') {
+        return true;
+    }
+    if ('x-precedence' in headers && headers['x-precedence'].toLowerCase() === 'auto_reply') {
+        return true;
+    }
+    if ('x-autorespond' in headers) {
         return true;
     }
     if ('x-autogenerated' in headers && ['forward', 'group', 'letter', 'mirror', 'redirect', 'reply'].includes(headers['x-autogenerated'].toLowerCase())) {
diff --git a/test.js b/test.js
index 0e59198..b974225 100644
--- a/test.js
+++ b/test.js
@@ -21,9 +21,9 @@ assert.ok(isAutoreply({ 'return-path': '<>' }));
 assert.ok(isAutoreply({ 'Preference': 'auto_reply' }));
 assert.ok(isAutoreply({ 'preference': 'auto_reply' }));
 assert.ok(!isAutoreply({ 'Preference': 'not_auto_reply' }));
-assert.ok(isAutoreply({ 'X-Preference': 'auto_reply' }));
-assert.ok(isAutoreply({ 'x-preference': 'auto_reply' }));
-assert.ok(!isAutoreply({ 'X-Preference': 'not_auto_reply' }));
+assert.ok(isAutoreply({ 'X-Precedence': 'auto_reply' }));
+assert.ok(isAutoreply({ 'x-precedence': 'auto_reply' }));
+assert.ok(!isAutoreply({ 'X-Precedence': 'not_auto_reply' }));
 
 // Test X-AutoRepsond header
 assert.ok(isAutoreply({ 'X-AutoRespond': '' }));