diff --git a/HISTORY.md b/HISTORY.md
index 5b8ec6e0..9e546ebc 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,6 +1,8 @@
 # vis.js history
 http://visjs.org
 
+## NOT YET RELEASED, verions 4.2.1--SNAPSHOT
+
 ## 2015-06-05, version 4.2.0
 
 ### General
diff --git a/bower.json b/bower.json
index f1dea701..138d8331 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "vis",
-  "version": "4.2.0",
+  "version": "4.2.1--SNAPSHOT",
   "main": ["dist/vis.min.js", "dist/vis.min.css"],
   "description": "A dynamic, browser-based visualization library.",
   "homepage": "http://visjs.org/",
diff --git a/package.json b/package.json
index b10e3e39..5143a2c5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "vis",
-  "version": "4.2.0",
+  "version": "4.2.0--SNAPSHOT",
   "description": "A dynamic, browser-based visualization library.",
   "homepage": "http://visjs.org/",
   "license": "(Apache-2.0 OR MIT)",