pyscript · ntoll · Feb 5, 2026 · Feb 5, 2026 · Feb 5, 2026 · Feb 5, 2026
diff --git a/docs/beginning-pyscript.md b/docs/beginning-pyscript.md
@@ -118,8 +118,8 @@ module, and a `<link>` to some PyScript specific CSS, in the document's
       <meta charset="utf-8" />
       <meta name="viewport" content="width=device-width,initial-scale=1" />
       <title>🦜 Polyglot - Piratical PyScript</title>
-      <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-      <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+      <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+      <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
   </head>
   <body>
 
@@ -165,8 +165,8 @@ In the end, our HTML should look like this:
       <meta charset="utf-8" />
       <meta name="viewport" content="width=device-width,initial-scale=1" />
       <title>🦜 Polyglot - Piratical PyScript</title>
-      <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-      <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+      <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+      <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
   </head>
   <body>
     <h1>Polyglot 🦜 💬 🇬🇧 ➡️ 🏴‍☠️</h1>
@@ -308,7 +308,7 @@ To run PyScript offline, without the need of a CDN or internet connection, read
 the [offline guide](user-guide/offline.md) section of the user guide.
 
 We also provide an `offline.zip` file with
-[each release](https://pyscript.net/releases/2026.1.1/). This file contains
+[each release](https://pyscript.net/releases/2026.2.1/). This file contains
 everything you need for an offline version of PyScript: PyScript itself,
 versions of Pyodide and MicroPython, and an index.html page from which you
 could create your offline-first PyScript work.

diff --git a/docs/example-apps/bouncing-ball/index.html b/docs/example-apps/bouncing-ball/index.html
@@ -4,8 +4,8 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width,initial-scale=1.0">
     <title>PyGame-CE Bouncing Ball</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, sans-serif;

diff --git a/docs/example-apps/colour-picker/index.html b/docs/example-apps/colour-picker/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Interactive Colour Picker</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, -apple-system, sans-serif;

diff --git a/docs/example-apps/display-demo/index.html b/docs/example-apps/display-demo/index.html
@@ -5,9 +5,9 @@
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Display Demo</title>
     <link rel="stylesheet" 
-      href="https://pyscript.net/releases/2026.1.1/core.css">
+      href="https://pyscript.net/releases/2026.2.1/core.css">
     <script type="module" 
-      src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+      src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, -apple-system, sans-serif;

diff --git a/docs/example-apps/note-taker/index.html b/docs/example-apps/note-taker/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Note Taker</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, sans-serif;

diff --git a/docs/example-apps/photobooth/index.html b/docs/example-apps/photobooth/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Photobooth</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, sans-serif;

diff --git a/docs/example-apps/pirate-translator/index.html b/docs/example-apps/pirate-translator/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>🦜 Polyglot - Piratical PyScript</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
   </head>
   <body>
     <h1>Polyglot 🦜 💬 🇬🇧 ➡️ 🏴‍☠️</h1>

diff --git a/docs/example-apps/prime-worker/index.html b/docs/example-apps/prime-worker/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Prime Numbers with Workers</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, sans-serif;

diff --git a/docs/example-apps/task-board-ffi/index.html b/docs/example-apps/task-board-ffi/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Task Board - FFI</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, -apple-system, sans-serif;

diff --git a/docs/example-apps/task-board-web/index.html b/docs/example-apps/task-board-web/index.html
@@ -4,8 +4,8 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>Task Board - pyscript.web</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
     <style>
       body {
         font-family: system-ui, -apple-system, sans-serif;

diff --git a/docs/faq.md b/docs/faq.md
@@ -58,41 +58,36 @@ This is the most common error new PyScript users face:
 
 #### When
 
-This error occurs when code running in a worker tries to access `window`
-or `document` objects that exist on the main thread.
+This error occurs when code running in a worker tries to access
+`window` or `document` objects from the main thread.
 
-The error indicates either **your web server is incorrectly configured**
-or **a `service-worker` attribute is missing from your script element**.
+It indicates one of three situations:
 
-Specifically, one of three situations applies:
+1. **Server misconfiguration:** Your script has a `worker` attribute and
+   accesses `window` or `document`, but your web server isn't configured to
+   enable SharedArrayBuffer/Atomics.
 
-Your web server configuration prevents the browser from enabling Atomics
-(a technology for cross-thread communication). When your script element
-has a `worker` attribute and your Python code uses `window` or
-`document` objects that exist on the main thread, this browser
-limitation causes failure unless you reconfigure your server.
+2. **Missing service-worker attribute:** You're using
+   `<script type="py-editor">` (which always runs in a worker) without
+   providing a `service-worker` attribute for fallback synchronous operations.
 
-You're using `<script type="py-editor">` (which always runs in a worker)
-without providing a fallback via a `service-worker` attribute on that
-element.
+3. **PyWorker without fallback:** You've created a `PyWorker` or `MPWorker`
+   instance without providing a `service_worker` fallback (see:
+   [this API class](./api/context.md/#pyscript.context.PyWorker)).
 
-You've explicitly created a `PyWorker` or `MPWorker` instance somewhere
-in your code without providing a `service_worker` fallback.
-
-The [workers guide](./user-guide/workers.md) documents all these cases
+The [workers guide](./user-guide/workers.md) documents all these use cases
 with code examples and solutions.
 
 #### Why
 
-For `document.getElementById('some-id').value` to work in a worker,
-JavaScript requires two primitives:
-
-[SharedArrayBuffer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer)
-allows multiple threads to read and write shared memory.
+Workers often require two browser based features to access main thread objects
+like `window` and `document`.
 
-[Atomics](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics)
-provides `wait(sab, index)` and `notify(sab, index)` to coordinate
-threads, where `sab` is a SharedArrayBuffer.
+1. [SharedArrayBuffer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer)
+   allows multiple threads to read and write shared memory.
+2. [Atomics](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics)
+   provides `wait(sab, index)` and `notify(sab, index)` to coordinate
+   threads, where `sab` is a SharedArrayBuffer.
 
 Whilst a worker waits for a main thread operation, it doesn't consume
 CPU. It idles until the referenced buffer index changes, effectively
@@ -105,8 +100,124 @@ responsive during heavy computation.
 
 Unfortunately, we cannot patch or work around these primitives - they're
 defined by web standards. However, various solutions exist for working
-within these limitations. The [workers guide](./user-guide/workers.md)
-explains how.
+within these limitations.
+
+The easiest fix is to ensure your webserver is correctly configured to
+serve responses with the following headers:
+
+```
+Access-Control-Allow-Origin: *
+Cross-Origin-Opener-Policy: same-origin
+Cross-Origin-Embedder-Policy: require-corp
+Cross-Origin-Resource-Policy: cross-origin
+```
+
+If you are unable to reconfigure your webserver (perhaps, for example,
+you're using a third party for hosting), you have two options:
+
+**Option 1:** `mini-coi`
+
+The `mini-coi` project ensures a browser's
+[complicated Cross Origin Isolation (COI) settings](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer#security_requirements)
+"just work" for web workers. This is especially useful when you have no
+control over the HTTP headers returned by the server.
+
+For performance reasons, this is the preferred option so Atomics works at
+native speed.
+
+The simplest way to use mini-coi is to copy the
+[`mini-coi.js`](https://raw.githubusercontent.com/WebReflection/mini-coi/main/mini-coi.js)
+file to the root of your website (i.e. `/`), and reference it as the first
+child tag in the `<head>` of your HTML documents:
+
+```html
+<html>
+  <head>
+    <script src="/mini-coi.js"></script>
+    <!-- etc -->
+  </head>
+  <!-- etc -->
+</html>
+```
+
+**Option 2:** `service-worker` attribute
+
+This allows you to slot in a custom
+[service worker](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API)
+to handle requirements for synchronous operations.
+
+Each `<script type="m/py">` or `<m/py-script>` may optionally have a
+`service-worker` attribute pointing to a locally served file (the same way
+`mini-coi.js` needs to be served).
+
+This file needs to orchestrate _coincident POST_ requests so that:
+
+* You can copy and paste
+  [the coincident Service Worker](https://cdn.jsdelivr.net/npm/coincident/dist/sw.js)
+  into your local project and point at that via the `service-worker`
+  attribute. This will not change the original behavior of your project, it
+  will not interfere with the default or pre-defined headers your application
+  uses already but it will **fallback to a (slower but working) synchronous
+  operation** that allows both `window` and `document` access in your worker
+  logic.
+* You can import 
+  [coincident listeners](https://github.com/WebReflection/coincident/blob/main/src/sabayon/listeners.js)
+  in your project and at least add the `fetch` one before your listeners. It
+  will automatically stop propagation when a request is meant to be handled
+  so that the rest of your logic will not be affected or change by any mean.
+
+```html
+<html>
+  <head>
+    <!-- PyScript link and script -->
+  </head>
+  <body>
+    <script type="py" service-worker="./sw.js" worker>
+      from pyscript import window, document
+
+      document.body.append("Hello PyScript!")
+    </script>
+  </body>
+</html>
+```
+
+!!! warning
+
+    Using _coincident_ as the fallback for synchronous operations via Atomics
+    should be **the last solution to consider**. It is inevitably slower than
+    using native Atomics.
+
+    If you must use `service-worker` attribute, always reduce the amount of
+    synchronous operations by caching references from the _main_ thread.
+
+    ```python
+    # ❌ THIS IS UNNECESSARILY SLOWER
+    from pyscript import document
+
+    # add a data-test="not ideal attribute"
+    document.body.dataset.test = "not ideal"
+    # read a data-test attribute
+    print(document.body.dataset.test)
+
+    # - - - - - - - - - - - - - - - - - - - - -
+
+    # ✔️ THIS IS FINE
+    from pyscript import document
+
+    # if needed elsewhere, reach it once
+    body = document.body
+    dataset = body.dataset
+
+    # add a data-test="not ideal attribute"
+    dataset.test = "not ideal"
+    # read a data-test attribute
+    print(dataset.test)
+    ```
+
+    In latter example the number of operations has been reduced from six to
+    just four. The rule of thumb is: _if you ever need a DOM reference more 
+    than once, cache it_.
+
 
 ### Borrowed proxy
 
@@ -430,7 +541,7 @@ versions or use `latest`:
 
 ```html
 <!-- Specific version (recommended for production). -->
-<script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+<script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
 
 <!-- Latest version (useful for development). -->
 <script type="module" src="https://pyscript.net/latest/core.js"></script>
@@ -461,7 +572,7 @@ You can create workers programmatically from JavaScript:
 
 ```html
 <script type="module">
-import { PyWorker } from "https://pyscript.net/releases/2026.1.1/core.js";
+import { PyWorker } from "https://pyscript.net/releases/2026.2.1/core.js";
 
 const worker = new PyWorker("./worker.py", {type: "pyodide"});
 

diff --git a/docs/index.md b/docs/index.md
@@ -6,8 +6,8 @@
 **Step 1:** Add these two lines to the `<head>` of your HTML document:
 
 ```html
-<link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css" />
-<script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+<link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css" />
+<script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
 ```
 
 **Step 2:** Start PyScript with a `<script>` tag in the `<body>` of your HTML document:

diff --git a/docs/user-guide/configuration.md b/docs/user-guide/configuration.md
@@ -667,8 +667,8 @@ Here's a complete example showing common configuration options:
   <head>
     <meta charset="utf-8" />
     <title>My PyScript App</title>
-    <link rel="stylesheet" href="https://pyscript.net/releases/2026.1.1/core.css">
-    <script type="module" src="https://pyscript.net/releases/2026.1.1/core.js"></script>
+    <link rel="stylesheet" href="https://pyscript.net/releases/2026.2.1/core.css">
+    <script type="module" src="https://pyscript.net/releases/2026.2.1/core.js"></script>
   </head>
   <body>
     <h1>Data Analysis</h1>

diff --git a/docs/user-guide/from_javascript.md b/docs/user-guide/from_javascript.md
@@ -41,7 +41,7 @@ serialised to formats JavaScript can understand.
 JavaScript code imports the storage module from PyScript core:
 
 ```javascript title="Access storage in JavaScript."
-import storage from 'https://pyscript.net/releases/2026.1.1/storage.js';
+import storage from 'https://pyscript.net/releases/2026.2.1/storage.js';
 
 
 const my_store = await storage(name="shared");
@@ -81,7 +81,7 @@ use Python from pure JavaScript without writing PyScript tags.
 Import the `donkey` function and create a worker with it:
 
 ```javascript title="Call for the PyScript donkey."
-import { donkey } from 'https://pyscript.net/releases/2026.1.1/core.js';
+import { donkey } from 'https://pyscript.net/releases/2026.2.1/core.js';
 
 const py_donkey = await donkey({
   type: 'mpy',        // Use MicroPython ('py' for Pyodide).

diff --git a/docs/user-guide/offline.md b/docs/user-guide/offline.md
@@ -30,7 +30,7 @@ libraries, the package files must also be available offline.
 ## Shortcut
 
 Helpfully, since the end of 2025, all
-[releases of PyScript](https://pyscript.net/releases/2026.1.1/)
+[releases of PyScript](https://pyscript.net/releases/2026.2.1/)
 have an associated `offline`
 zip file containing everything you need. Just download it, unpack it and
 start to modify the content of the `index.html` found therein to your needs.