closes #3585

src/controllers/accounts.js

@@ -374,6 +374,8 @@ accountsController.accountEdit = function(req, res, callback) {
 			return callback(err);
 		}
 
+		userData['username:disableEdit'] = parseInt(meta.config['username:disableEdit'], 10) === 1;
+		
 		userData.hasPassword = !!password;
 		userData.title = '[[pages:account/edit, ' + userData.username + ']]';
 		userData.breadcrumbs = helpers.buildBreadcrumbs([{text: userData.username, url: '/user/' + userData.userslug}, {text: '[[user:edit]]'}]);

src/socket.io/user.js

@@ -231,6 +231,10 @@ SocketUser.updateProfile = function(socket, data, callback) {
 			return callback(err);
 		}
 
+		if (parseInt(meta.config['username:disableEdit'], 10) === 1) {
+			data.username = oldUserData.username;
+		}
+
 		update(oldUserData, callback);
 	});
 };

src/views/admin/settings/user.tpl

@@ -44,6 +44,12 @@
 	<div class="col-sm-2 col-xs-12 settings-header">Account Settings</div>
 	<div class="col-sm-10 col-xs-12">
 		<form>
+			<div class="checkbox">
+				<label class="mdl-switch mdl-js-switch mdl-js-ripple-effect">
+					<input class="mdl-switch__input" type="checkbox" data-field="username:disableEdit">
+					<span class="mdl-switch__label"><strong>Disable username changes</strong></span>
+				</label>
+			</div>
 			<div class="checkbox">
 				<label class="mdl-switch mdl-js-switch mdl-js-ripple-effect">
 					<input class="mdl-switch__input" type="checkbox" data-field="allowAccountDelete" checked>