diff --git a/README.md b/README.md
index 7821f16..50a5eea 100644
--- a/README.md
+++ b/README.md
@@ -4,10 +4,6 @@
 
 Web server directory index customization with preview, pagination, download — h5ai.
 
-![SDI h5ai screenshot](https://repository-images.githubusercontent.com/806409657/7e051d9f-5900-4ff1-9b1c-d96cfd9bfbd6)
-
----
-
 ## SDI — h5ai
 
 Unpack server directory index h5ai to your `/www/public/*.*`   
@@ -16,13 +12,33 @@ and access your `https://example.com/public` or `http://localhost`
 Whatever you drop on the Public folder will automatically
 be available on the web server and you can easily share the links.
 
-## Server Index redirection
+### 1. Server AutoIndex
+
+Enables or disables automatic directory listing for directories missing an index page.
 
 Add the public directory index to your server configuration.   
 You can also redirect every access to the /public/ directory.   
-See how to redirect [Apache httpd, lighttpd, and nginx][wiki]  
+See how to redirect [Apache httpd, lighttpd, and nginx][wiki] 
+
+### 2. JavaScript Modules
+
+Default server configuration does not serve <code>.mjs</code>   
+PDF.js requires this Mime Type in your server configuration,   
+otherwise you'll get a browser error :
+
+> Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/html"
+
+See [Apache httpd, lighttpd, and nginx][wiki] to add <code>.mjs</code> JavaScript MIME type. 
+
+---
 
-## SDI — CRUD
+![SDI h5ai screenshot](screen.png)
+
+---
+
+## Development Note  
+
+### SDI — CRUD
 
 [Branch local][wiki] to create, read, upload and delete   
 Authenticate using password-based Accounts.
@@ -33,25 +49,57 @@ Authenticate using password-based Accounts.
   [project wiki][wiki].
 * For bug reports and feature requests please use [issues][github-issues].
 
----
-
-### Development 
 
 #### Build
 
 There are installation ready packages for the latest [releases][release] and
-[dev builds][develop]. But to build **h5ai** yourself either `git clone` or
-download the repository. From within the root folder run the following
-commands to find a fresh zipball in folder `build` (tested on linux only,
-requires [`node 10.0+`][node] to be installed, might work on other
-configurations).
+[dev builds][develop].   
+But to build **h5ai** yourself either `git clone` or
+download SDI—CRUD.   
+
+Change Node.js version with [Node Version Manager][nvm]  
+Install the proposed node version locally [`node 16.17.0`][node]   
+Cross-env tested on Linux and Windows,   
+might work on other configurations.   
+
+```sh
+nvm install 16.17.0 
+```
+
+List node versions
+
+```sh
+nvm ls
+```
+
+and in order to use it:
+
+```sh
+nvm use 16.17.0
+```
+
+From within the root folder of sdi-crud run the following commands 
 
 ```sh
 > npm install
 > npm run build
 ```
 
-#### Development cross env
+Find a fresh zipball in folder `build` 
+
+
+#### Development cross-env
+
+Linux   
+
+```sh
+> npm run clean
+> npm run reinstall
+> npm run rebuild
+
+```
+
+Windows   
 
 ```sh
 > npm run clean-win
@@ -100,6 +148,7 @@ too. Exceptions are some [Material Design icons][material-design-icons] (CC BY 4
 [release]: https://github.com/gigamaster/server-directory-index/releases
 [develop]: https://github.com/gigamaster/server-directory-index
 [node]: https://nodejs.org
+[nvm]: https://github.com/nvm-sh/nvm
 [material-design-icons]: https://github.com/google/material-design-icons
 
 [license-img]: https://img.shields.io/badge/license-MIT-a0a060.svg?style=flat-square
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