diff --git a/.github/stale.yml b/.github/stale.yml
new file mode 100644
index 0000000000..d9d001fb69
--- /dev/null
+++ b/.github/stale.yml
@@ -0,0 +1,12 @@
+# Mark issues stale after 1 year
+daysUntilStale: 365
+# Delete stale issues after 2 years
+daysUntilClose: 730
+markComment: >
+  This issue has been automatically marked as stale because it has not had
+  recent activity. It will be closed if no further activity occurs. Thank you
+  for your contributions.
+closeComment: >
+  This issue has been automatically closed after being marked stale. If you're
+  still facing this problem with the above solution, please comment and we'll
+  reopen!
diff --git a/lib/mixins/element-mixin.js b/lib/mixins/element-mixin.js
index 9dbc0fd965..fb5ee7ec01 100644
--- a/lib/mixins/element-mixin.js
+++ b/lib/mixins/element-mixin.js
@@ -24,7 +24,7 @@ import { wrap } from '../utils/wrap.js';
  * Current Polymer version in Semver notation.
  * @type {string} Semver notation of the current version of Polymer.
  */
-export const version = '3.3.1';
+export const version = '3.4.0';
 
 export const builtCSS = window.ShadyCSS && window.ShadyCSS['cssBuild'];
 
diff --git a/package-lock.json b/package-lock.json
index df28fbfa41..93199ea4a2 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "@polymer/polymer",
-  "version": "3.3.1",
+  "version": "3.4.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 851ed99d05..8a7e850a65 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@polymer/polymer",
-  "version": "3.3.1",
+  "version": "3.4.0",
   "description": "The Polymer library makes it easy to create your own web components. Give your element some markup and properties, and then use it on a site. Polymer provides features like dynamic templates and data binding to reduce the amount of boilerplate you need to write",
   "main": "polymer-element.js",
   "module": "polymer-element.js",