diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 0ee8c01..2537c1f 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.3.0"
+  ".": "0.4.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index aab4e58..9e73544 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## [0.4.0](https://github.com/voidberg/quarto/compare/quarto-v0.3.0...quarto-v0.4.0) (2026-06-30)
+
+
+### Features
+
+* add series/collection metadata (series, seriesIndex) ([39e31c6](https://github.com/voidberg/quarto/commit/39e31c63f3efb3fd954596264bf5b5db727183af))
+
 ## [0.3.0](https://github.com/voidberg/quarto/compare/quarto-v0.2.0...quarto-v0.3.0) (2026-06-29)
 
 
diff --git a/jsr.json b/jsr.json
index d70e990..2ff2980 100644
--- a/jsr.json
+++ b/jsr.json
@@ -1,6 +1,6 @@
 {
   "name": "@voidberg/quarto",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "license": "MIT",
   "exports": "./src/index.ts",
   "publish": {
diff --git a/package-lock.json b/package-lock.json
index 54e3e38..d5f2f3b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@voidberg/quarto",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@voidberg/quarto",
-      "version": "0.3.0",
+      "version": "0.4.0",
       "license": "MIT",
       "dependencies": {
         "fflate": "^0.8.2",
diff --git a/package.json b/package.json
index 25f8b6f..bb4d5bf 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@voidberg/quarto",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "Generate EPUB3 and Kobo kepub files from HTML — runtime-agnostic, in-memory, with optional table of contents.",
   "keywords": [
     "epub",