diff --git a/jslint.js b/jslint.js
index 734e733e5..603a64275 100644
--- a/jslint.js
+++ b/jslint.js
@@ -1,5 +1,5 @@
 // jslint.js
-// 2017-01-10
+// 2017-01-13
 // Copyright (c) 2015 Douglas Crockford  (www.JSLint.com)
 
 // Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -4371,6 +4371,11 @@ var jslint = (function JSLint() {
                 thing.constant = true;
             }
             break;
+        case "!":
+            if (thing.expression.constant === true) {
+                warn("unexpected_a", thing);
+            }
+            break;
         default:
             if (thing.expression.constant === true) {
                 thing.constant = true;
@@ -4883,7 +4888,7 @@ var jslint = (function JSLint() {
         }
         return {
             directives: directives,
-            edition: "2017-01-10",
+            edition: "2017-01-13",
             exports: exports,
             froms: froms,
             functions: functions,