diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index b5ddef8..1772e6f 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-    ".": "0.11.0"
+    ".": "1.0.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d02c501..47a18b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Changelog
 
+## [1.0.0](https://github.com/b-long/opentdf-python-sdk/compare/otdf-python-v0.11.0...otdf-python-v1.0.0) (2026-09-22)
+
+
+### ⚠ BREAKING CHANGES
+
+* **tdf:** TDF archives are now written with the spec-mandated manifest.json entry instead of 0.manifest.json. Readers accept both names. Files written by this version cannot be opened by released otdfctl, upstream Go, Java, or JS SDKs until they add a manifest.json fallback.
+
+### Features
+
+* **tdf:** spec-compliant container — manifest.json entry, payload from payload.url ([#188](https://github.com/b-long/opentdf-python-sdk/issues/188)) ([4216468](https://github.com/b-long/opentdf-python-sdk/commit/42164681ddae1cc161331f835b3358dc7442052f))
+
 ## [0.11.0](https://github.com/b-long/opentdf-python-sdk/compare/otdf-python-v0.10.2...otdf-python-v0.11.0) (2026-09-15)
 
 
diff --git a/packages/otdf-python-proto/pyproject.toml b/packages/otdf-python-proto/pyproject.toml
index 5408a9a..a215f01 100644
--- a/packages/otdf-python-proto/pyproject.toml
+++ b/packages/otdf-python-proto/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "otdf-python-proto"
-version = "0.11.0"
+version = "1.0.0"
 description = "Generated protobuf files for OpenTDF Python SDK"
 readme = "README.md"
 authors = [
diff --git a/packages/otdf-python/pyproject.toml b/packages/otdf-python/pyproject.toml
index ce4ea80..24825bf 100644
--- a/packages/otdf-python/pyproject.toml
+++ b/packages/otdf-python/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "otdf-python"
-version = "0.11.0"
+version = "1.0.0"
 description = "Unofficial OpenTDF SDK for Python"
 readme = "README.md"
 authors = [
diff --git a/uv.lock b/uv.lock
index a022767..4a85346 100644
--- a/uv.lock
+++ b/uv.lock
@@ -451,7 +451,7 @@ wheels = [
 
 [[package]]
 name = "otdf-python"
-version = "0.11.0"
+version = "1.0.0"
 source = { editable = "packages/otdf-python" }
 dependencies = [
     { name = "connect-python" },
@@ -500,7 +500,7 @@ dev = [
 
 [[package]]
 name = "otdf-python-proto"
-version = "0.11.0"
+version = "1.0.0"
 source = { editable = "packages/otdf-python-proto" }
 dependencies = [
     { name = "connect-python" },