Small cleanup and mention that Elastic requires IE 11+

README.md

@@ -19,14 +19,11 @@ application-like user interface. It provides full functionality you expect
 from an email client, including MIME support, address book, folder management,
 message searching and spell checking. Roundcube Webmail is written in PHP and
 requires the MySQL, PostgreSQL or SQLite database. With its plugin API it is
-easily extendable and the user interface is fully customizable using skins
-which are pure XHTML and CSS 2.
+easily extendable and the user interface is fully customizable using skins.
 
-The code is mainly written in PHP and is designed to run on a webserver.
-It includes other open-source classes/libraries from [PEAR][pear],
-an IMAP library derived from [IlohaMail][iloha] the [TinyMCE][tinymce] rich
-text editor, [Googiespell][googiespell] (archive) library for spell checking or
-the [HTML5-PHP][html5-php] sanitizer by Masterminds.
+The code designed to run on a webserver is mainly written in PHP and Javascript.
+It includes a custom framework with an IMAP library derived from [IlohaMail][iloha]
+and requires a set of external libraries (see composer.json and jsdeps.json files).
 
 The current default skin 'Larry' was kindly created by FLINT / Büro für
 Gestaltung, Berne, Switzerland.
@@ -49,7 +46,7 @@ support from there. This currently includes:
 - Chrome: (Current - 1) and Current
 - Edge: (Current - 1) and Current
 - Firefox: (Current - 1) and Current, ESR
-- Internet Explorer: 9+
+- Internet Explorer: 9+ (11+ for the Elastic skin)
 - Safari: (Current - 1) and Current
 - Opera: Current
 
@@ -102,11 +99,7 @@ You're always welcome to send a message to the project admin:
 hello(at)roundcube(dot)net
 
 
-[pear]:         https://pear.php.net/
 [iloha]:        https://sourceforge.net/projects/ilohamail/
-[tinymce]:      https://www.tiny.cloud/
-[googiespell]:  https://web.archive.org/web/20170314162746/orangoo.com/labs/GoogieSpell/
-[html5-php]:    https://github.com/Masterminds/html5-php
 [gpl]:          https://www.gnu.org/licenses/
 [license]:      https://roundcube.net/license
 [contrib]:      https://roundcube.net/contribute