Update readme

#14

Author: robincornett

readme.md

@@ -1,5 +1,41 @@
 # EDD Software Licensing SDK
 
+A drop-in solution for WordPress plugin and theme developers to quickly integrate Easy Digital Downloads Software Licensing into their products without complex setup or custom admin interfaces.
+
+## Overview
+
+The EDD Software Licensing SDK streamlines the process of adding licensing functionality to your WordPress plugins and themes. Instead of building custom settings pages and handling license validation manually, this SDK provides a complete licensing solution that seamlessly integrates with existing WordPress admin interfaces.
+
+### Key Features
+
+- **Zero-configuration licensing** - Add licensing support with just a few lines of code
+- **Native WordPress integration** - License fields appear directly in plugin action links and theme admin menus
+- **Automatic updates** - Handles secure update delivery for licensed products
+- **No custom admin pages** - Uses WordPress's existing interface patterns
+- **Flexible deployment** - Works as a standalone plugin or Composer package
+- **Developer-friendly** - Minimal code required, maximum functionality provided
+
+### How It Works
+
+For **plugins**, the SDK adds a "Manage License" link directly in the plugin list on the Plugins admin screen. Clicking this link opens a modal where users can enter and activate their license key.
+
+For **themes**, a "Theme License" menu item is automatically added to the Appearance menu, providing easy access to license management via the modal.
+
+The SDK handles all the complex licensing logic behind the scenes:
+- License key validation and activation
+- Automatic update notifications and delivery
+- License status tracking and renewal reminders
+- Secure communication with your EDD store
+
+### Perfect For
+
+- Plugin developers who want to focus on features, not licensing infrastructure
+- Theme authors looking for a professional licensing solution
+- Developers transitioning from other licensing systems
+- Anyone who wants licensing integration without reinventing the wheel
+
+## Installation
+
 You can run the SDK as a standalone plugin on your site, or install it as a Composer package in your theme or plugin:
 
 ```
@@ -17,7 +53,7 @@ You can run the SDK as a standalone plugin on your site, or install it as a Comp
   }
 }
 
-## Example Usage
+### Example Usage
 
 Plugin:
 ```php
@@ -55,11 +91,12 @@ add_action(
 );
 ```
 
-## Arguments
+### Arguments
 
 - `id` - Plugin/theme slug.
 - `url` - The store URL.
 - `item_id` - The item ID (on your store).
 - `version` - The current version number.
 - `file` - The main plugin file. Not needed for themes.
 - `type` - `plugin` or `theme`. Not needed for plugins.
+- `weekly_check` - Optional: whether to make a weekly request to confirm the license status. Defaults to true.

src/Updaters/Updater.php

@@ -49,7 +49,7 @@ abstract class Updater {
 	 */
 	public function __construct( $api_url, $args = array() ) {
 		$this->api_url = $api_url;
-		$this->file    = $args['file'];
+		$this->file    = $args['file'] ?? '';
 		$defaults      = $this->get_api_request_defaults();
 		$this->args    = array_merge( $defaults, array_intersect_key( $args, $defaults ) );
 		$this->add_listeners();