diff --git a/package-lock.json b/package-lock.json
index 1863535..a9216d7 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "lp-model",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "lp-model",
-      "version": "0.3.0",
+      "version": "0.4.0",
       "license": "MIT",
       "devDependencies": {
         "@rollup/plugin-terser": "^0.4.4",
diff --git a/package.json b/package.json
index d0cc4dd..9cb58cb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "lp-model",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "JavaScript package for modelling (Integer) Linear Programs",
   "scripts": {
     "build": "rollup -c",