set content-length header for html if there is no compression active;

PgCache_ContentGrabber.php

@@ -2169,6 +2169,15 @@ private function _maybe_save_cached_result( $buffer, $response_headers, $has_dyn
 		// Calculate content etag
 		$etag = md5( $buffer );
 
+		// Pass content-length in case there are no compression methods enabled
+		if(
+			$compressions_to_store === [false] &&
+			$this->_config->get_boolean( 'browsercache.enabled' ) &&
+			(!$this->_config->get_boolean( 'browsercache.html.compression' ) && !$this->_config->get_boolean( 'browsercache.html.brotli' ))
+		){
+			$headers['Content-Length'] = strlen($buffer);
+		}
+
 		// Send headers
 		$this->_send_headers( $is_404, $time, $etag, $compression_header,
 			$headers );

composer.json

@@ -2,7 +2,7 @@
     "name": "glomex/w3-total-cache",
     "description": "Altered version of W3TC plugin with support for internal Glomex infrastructure",
     "type": "wordpress-plugin",
-    "version": "2.1.8.2",
+    "version": "2.1.8.3",
     "require-dev": {
 		"roave/security-advisories": "dev-master"
 	},

w3-total-cache-api.php

@@ -5,7 +5,7 @@
 }
 
 define( 'W3TC', true );
-define( 'W3TC_VERSION', '2.1.8.2' );
+define( 'W3TC_VERSION', '2.1.8.3' );
 define( 'W3TC_POWERED_BY', 'W3 Total Cache' );
 define( 'W3TC_EMAIL', 'w3tc@w3-edge.com' );
 define( 'W3TC_TEXT_DOMAIN', 'w3-total-cache' );

w3-total-cache.php

@@ -3,7 +3,7 @@
  * Plugin Name:       W3 Total Cache
  * Plugin URI:        https://www.boldgrid.com/totalcache/
  * Description:       The highest rated and most complete WordPress performance plugin. Dramatically improve the speed and user experience of your site. Add browser, page, object and database caching as well as minify and content delivery network (CDN) to WordPress.
- * Version:           2.1.8.2
+ * Version:           2.1.8.3
  * Requires at least: 3.8
  * Requires PHP:      5.6
  * Author:            BoldGrid