diff --git a/plugins/libkolab/composer.json b/plugins/libkolab/composer.json
index dc15b632..f9a714f8 100644
--- a/plugins/libkolab/composer.json
+++ b/plugins/libkolab/composer.json
@@ -1,31 +1,32 @@
 {
     "name": "kolab/libkolab",
     "type": "roundcube-plugin",
     "description": "Plugin to setup a basic environment for the interaction with a Kolab server.",
     "homepage": "https://git.kolab.org/diffusion/RPK/",
     "license": "AGPLv3",
     "version": "3.4.0",
     "authors": [
         {
             "name": "Thomas Bruederli",
             "email": "bruederli@kolabsys.com",
             "role": "Lead"
         },
         {
             "name": "Aleksander Machniak",
             "email": "machniak@kolabsys.com",
             "role": "Developer"
         }
     ],
     "repositories": [
         {
             "type": "composer",
             "url": "http://plugins.roundcube.net"
         }
     ],
     "require": {
         "php": ">=5.3.0",
         "roundcube/plugin-installer": ">=0.1.3",
-        "caxy/php-htmldiff": "dev-master"
+        "pear/http_request2": "~2.3.0",
+        "caxy/php-htmldiff": "~0.1.7"
     }
 }