flet-dev · FeodorFitsner · Jul 20, 2026 · Jul 20, 2026 · Jul 20, 2026
diff --git a/src/serious_python/CHANGELOG.md b/src/serious_python/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 4.3.6
+
+* **Windows:** fix startup with non-ASCII app paths or environment values — Dart FFI strings (UTF-8) are now converted to UTF-16 before being passed to the Windows CRT, so paths/env values are no longer corrupted through the process ANSI code page, and Python UTF-8 mode is enabled before `Py_Initialize()`. See `serious_python_windows` 4.3.6 and flet-dev/flet#6641.
+* Bundled python-build snapshot re-pinned to **20260720** (`dart_bridge` **1.5.0 → 1.5.1**, which carries the Windows fix above). Python versions (**3.12.13 / 3.13.14 / 3.14.6**) are unchanged.
+
 ## 4.3.4
 
 * **Windows/Linux:** desktop apps on Python **3.14** no longer crash at startup with `ModuleNotFoundError: No module named '_pyrepl'` when the app (or a dependency, e.g. NLTK) imports `pydoc` or `pdb`. `_pyrepl` was pruned from the desktop stdlib as a dev-only module, but 3.14's `pydoc`/`pdb` import it at module load. See `serious_python_windows` / `serious_python_linux` 4.3.4 and flet-dev/serious-python#236.

diff --git a/src/serious_python/lib/src/python_versions.dart b/src/serious_python/lib/src/python_versions.dart
@@ -1,5 +1,5 @@
 // GENERATED by `dart run serious_python:gen_version_tables` from python-build's
-// manifest.json (release 20260719). Do not edit by hand — edit python-build's
+// manifest.json (release 20260720). Do not edit by hand — edit python-build's
 // manifest.json, cut a release, bump `pythonReleaseDate`, and regenerate.
 
 const pythonVersionEnvironmentVariable = "SERIOUS_PYTHON_VERSION";
@@ -10,8 +10,8 @@ const pyodideVersionEnvironmentVariable = "SERIOUS_PYTHON_PYODIDE_VERSION";
 const dartBridgeVersionEnvironmentVariable = "DART_BRIDGE_VERSION";
 
 /// python-build release the bundled runtimes come from (YYYYMMDD).
-const pythonReleaseDate = "20260719";
-const dartBridgeVersion = "1.5.0";
+const pythonReleaseDate = "20260720";
+const dartBridgeVersion = "1.5.1";
 const defaultPythonVersion = "3.14";
 
 class PythonRelease {

diff --git a/src/serious_python/pubspec.yaml b/src/serious_python/pubspec.yaml
@@ -2,7 +2,7 @@ name: serious_python
 description: A cross-platform plugin for adding embedded Python runtime to your Flutter apps.
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 4.3.4
+version: 4.3.6
 
 platforms:
   ios:

diff --git a/src/serious_python_android/CHANGELOG.md b/src/serious_python_android/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.3.6
+
+* Re-pins the bundled python-build snapshot to **20260720** (`dart_bridge` **1.5.0 → 1.5.1**). 1.5.1 is a Windows-only UTF-8 startup fix (see `serious_python_windows` 4.3.6); the Android runtime is functionally unchanged from 20260719.
+
 ## 4.3.4
 
 * Re-pins the bundled python-build snapshot to **20260719** (previously 20260714). The snapshot un-prunes `_pyrepl` on Windows/Linux desktop only; Android already shipped `_pyrepl` (un-pruned in 4.3.2), so these runtimes are byte-identical to 20260714.

diff --git a/src/serious_python_android/android/build.gradle.kts b/src/serious_python_android/android/build.gradle.kts
@@ -21,7 +21,7 @@ buildscript {
 }
 
 group = "com.flet.serious_python_android"
-version = "4.3.4"
+version = "4.3.6"
 
 rootProject.allprojects {
     repositories {

diff --git a/src/serious_python_android/android/python_versions.properties b/src/serious_python_android/android/python_versions.properties
@@ -1,8 +1,8 @@
 # GENERATED by `dart run serious_python:gen_version_tables` from
-# python-build manifest.json (release 20260719). Do not edit by hand.
+# python-build manifest.json (release 20260720). Do not edit by hand.
 default_python_version=3.14
-dart_bridge_version=1.5.0
-python_build_release_date=20260719
+dart_bridge_version=1.5.1
+python_build_release_date=20260720
 3.12.full_version=3.12.13
 3.12.android_abis=arm64-v8a,x86_64,armeabi-v7a
 3.13.full_version=3.13.14

diff --git a/src/serious_python_android/pubspec.yaml b/src/serious_python_android/pubspec.yaml
@@ -2,7 +2,7 @@ name: serious_python_android
 description: Android implementation of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 4.3.4
+version: 4.3.6
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

diff --git a/src/serious_python_darwin/CHANGELOG.md b/src/serious_python_darwin/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.3.6
+
+* Re-pins the bundled python-build snapshot to **20260720** (`dart_bridge` **1.5.0 → 1.5.1**). 1.5.1 is a Windows-only UTF-8 startup fix (see `serious_python_windows` 4.3.6); the iOS/macOS runtimes are functionally unchanged from 20260719.
+
 ## 4.3.4
 
 * Re-pins the bundled python-build snapshot to **20260719** (previously 20260714). The snapshot un-prunes `_pyrepl` on Windows/Linux desktop (fixing a 3.14 `pydoc`/`pdb` crash — see `serious_python_windows` / `serious_python_linux` 4.3.4); iOS/macOS already shipped `_pyrepl` (un-pruned in 4.3.2), so these runtimes are byte-identical to 20260714. No iOS/macOS-affecting changes.

diff --git a/src/serious_python_darwin/darwin/python_versions.properties b/src/serious_python_darwin/darwin/python_versions.properties
@@ -1,8 +1,8 @@
 # GENERATED by `dart run serious_python:gen_version_tables` from
-# python-build manifest.json (release 20260719). Do not edit by hand.
+# python-build manifest.json (release 20260720). Do not edit by hand.
 default_python_version=3.14
-dart_bridge_version=1.5.0
-python_build_release_date=20260719
+dart_bridge_version=1.5.1
+python_build_release_date=20260720
 3.12.full_version=3.12.13
 3.12.android_abis=arm64-v8a,x86_64,armeabi-v7a
 3.13.full_version=3.13.14

diff --git a/src/serious_python_darwin/darwin/serious_python_darwin.podspec b/src/serious_python_darwin/darwin/serious_python_darwin.podspec
@@ -4,7 +4,7 @@
 #
 Pod::Spec.new do |s|
   s.name             = 'serious_python_darwin'
-  s.version          = '4.3.4'
+  s.version          = '4.3.6'
   s.summary          = 'A cross-platform plugin for adding embedded Python runtime to your Flutter apps.'
   s.description      = <<-DESC
   A cross-platform plugin for adding embedded Python runtime to your Flutter apps.

diff --git a/src/serious_python_darwin/pubspec.yaml b/src/serious_python_darwin/pubspec.yaml
@@ -2,7 +2,7 @@ name: serious_python_darwin
 description: iOS and macOS implementations of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 4.3.4
+version: 4.3.6
 
 environment:
   # The Swift Package Manager build path needs Flutter 3.44 / Dart 3.11 (the

diff --git a/src/serious_python_linux/CHANGELOG.md b/src/serious_python_linux/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.3.6
+
+* Re-pins the bundled python-build snapshot to **20260720** (`dart_bridge` **1.5.0 → 1.5.1**). 1.5.1 is a Windows-only UTF-8 startup fix (see `serious_python_windows` 4.3.6); the Linux runtime is functionally unchanged from 20260719.
+
 ## 4.3.4
 
 * **Fix `ModuleNotFoundError: No module named '_pyrepl'` on Python 3.14.** `_pyrepl` was pruned from the bundled Linux stdlib as a dev-only / interactive-REPL module, but CPython 3.14's `pydoc` (and `pdb`) import it at module load — so any app importing `pydoc`/`pdb`/`pytest`, or a dependency that does (e.g. NLTK → `pydoc`), crashed at startup. `_pyrepl` is no longer pruned. Re-pins the bundled python-build snapshot to **20260719** (previously 20260714). ([flet-dev/serious-python#236](https://github.com/flet-dev/serious-python/issues/236))

diff --git a/src/serious_python_linux/linux/python_versions.properties b/src/serious_python_linux/linux/python_versions.properties
@@ -1,8 +1,8 @@
 # GENERATED by `dart run serious_python:gen_version_tables` from
-# python-build manifest.json (release 20260719). Do not edit by hand.
+# python-build manifest.json (release 20260720). Do not edit by hand.
 default_python_version=3.14
-dart_bridge_version=1.5.0
-python_build_release_date=20260719
+dart_bridge_version=1.5.1
+python_build_release_date=20260720
 3.12.full_version=3.12.13
 3.12.android_abis=arm64-v8a,x86_64,armeabi-v7a
 3.13.full_version=3.13.14

diff --git a/src/serious_python_linux/pubspec.yaml b/src/serious_python_linux/pubspec.yaml
@@ -2,7 +2,7 @@ name: serious_python_linux
 description: Linux implementations of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 4.3.4
+version: 4.3.6
 
 environment:
   sdk: '>=3.1.3 <4.0.0'

diff --git a/src/serious_python_platform_interface/CHANGELOG.md b/src/serious_python_platform_interface/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.3.6
+
+* Version bump aligning with the `serious_python_*` 4.3.6 release (Windows UTF-8 startup fix via `dart_bridge` 1.5.1). No interface changes.
+
 ## 4.3.4
 
 * Version bump aligning with the `serious_python_*` 4.3.4 release (desktop `_pyrepl` fix + Android `flet debug` cache fix). No interface changes.

diff --git a/src/serious_python_platform_interface/pubspec.yaml b/src/serious_python_platform_interface/pubspec.yaml
@@ -2,7 +2,7 @@ name: serious_python_platform_interface
 description: A common platform interface for the serious_python plugin.
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 4.3.4
+version: 4.3.6
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

diff --git a/src/serious_python_windows/CHANGELOG.md b/src/serious_python_windows/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.3.6
+
+* **Fix Windows startup when app paths or environment values contain non-ASCII characters.** Dart FFI strings arrive as UTF-8, but the Windows boundary passed them straight to the ANSI CRT (`_putenv_s`, `fopen`), corrupting paths/env values through the process code page. The runtime now converts UTF-8 → UTF-16 and uses the wide CRT APIs (`_wputenv_s`, `_wfopen_s`), enables Python UTF-8 mode before `Py_Initialize()`, sets `PYTHONUTF8=1` for multiprocessing helpers, and treats embedded env-setup failures as fatal. Delivered via `dart_bridge` **1.5.1** (bundled python-build snapshot re-pinned to **20260720**). ([flet-dev/flet#6641](https://github.com/flet-dev/flet/issues/6641))
+
 ## 4.3.4
 
 * **Fix `ModuleNotFoundError: No module named '_pyrepl'` on Python 3.14.** `_pyrepl` was pruned from the bundled Windows stdlib as a dev-only / interactive-REPL module, but CPython 3.14's `pydoc` (and `pdb`) import it at module load — so any app importing `pydoc`/`pdb`/`pytest`, or a dependency that does (e.g. NLTK → `pydoc`), crashed at startup. `_pyrepl` is no longer pruned. Re-pins the bundled python-build snapshot to **20260719** (previously 20260714). ([flet-dev/serious-python#236](https://github.com/flet-dev/serious-python/issues/236))

diff --git a/src/serious_python_windows/pubspec.yaml b/src/serious_python_windows/pubspec.yaml
@@ -2,7 +2,7 @@ name: serious_python_windows
 description: Windows implementations of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 4.3.4
+version: 4.3.6
 
 environment:
   sdk: '>=3.1.3 <4.0.0'

diff --git a/src/serious_python_windows/windows/python_versions.properties b/src/serious_python_windows/windows/python_versions.properties
@@ -1,8 +1,8 @@
 # GENERATED by `dart run serious_python:gen_version_tables` from
-# python-build manifest.json (release 20260719). Do not edit by hand.
+# python-build manifest.json (release 20260720). Do not edit by hand.
 default_python_version=3.14
-dart_bridge_version=1.5.0
-python_build_release_date=20260719
+dart_bridge_version=1.5.1
+python_build_release_date=20260720
 3.12.full_version=3.12.13
 3.12.android_abis=arm64-v8a,x86_64,armeabi-v7a
 3.13.full_version=3.13.14