diff --git a/package-lock.json b/package-lock.json
index ed102eb..b07a571 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "epubavocado",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index ad9e706..0134279 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "epubavocado",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "I am an EPUB object model aspiring to be standards compliant.",
   "main": "lib/cjs/models.js",
   "module": "lib/esm/models.js",