wget http://appcenter-test.software-univention.de/univention-repository/4.2/maintained/component/maildisclaimer_20171106160114/all/univention-ckeditor_4.5.7-1_all.deb
wget http://appcenter-test.software-univention.de/univention-repository/4.2/maintained/component/maildisclaimer_20171106160114/all/univention-management-console-module-maildisclaimer_1.1.0-1_all.deb


dpkg -i univention-ckeditor_4.5.7-1_all.deb 
dpkg -i univention-management-console-module-maildisclaimer_1.1.0-1_all.deb 

but 

dojo.js.uncompressed.js:31729 Uncaught TypeError: Cannot read property 'value' of undefined
    at Object._setValueAttr (http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo/dojo.js:633:277)
    at Object.d (http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo/dojo.js:1157:92)
    at Object._setValueAttr (http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo/dojo.js:652:36)
    at Object.d (http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo/dojo.js:1157:92)
    at http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo/dojo.js:819:321
    at Object.<anonymous> (http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo-ckeditor/Editor.js:86:25)
    at a.<anonymous> (http://10.200.7.80/univention-management-console/js_$20170812100537$/dojo/dojo.js:820:130)
    at a.<anonymous> (http://10.200.7.80/univention-management-console/js_$20170812100537$/ckeditor/ckeditor.js:254:418)
    at a.(anonymous function) (http://10.200.7.80/univention-management-console/js_$20170812100537$/ckeditor/ckeditor.js:11:113)
    at a.n (http://10.200.7.80/univention-management-console/js_$20170812100537$/ckeditor/ckeditor.js:10:224)


diff -Nur modules.orig/appcenter-selfservice/AppPage.js modules/appcenter-selfservice/AppPage.js
--- modules.orig/appcenter-selfservice/AppPage.js	2017-12-08 11:08:38.921143000 +0100
+++ modules/appcenter-selfservice/AppPage.js	2017-12-08 14:27:41.961143000 +0100
@@ -58,8 +58,10 @@
 	"./SVGUploader",
 	"./RichTextEditor",
 	"./ThumbnailDndList",
+	"ckeditor/ckeditor",
+	"dojo-ckeditor/Editor",
 	"umc/i18n!umc/modules/appcenter-selfservice"
-], function(declare, lang, array, domClass, Dialog, registry, NumberTextBox, _ColorPicker, color, validate, dialog, tools, ContainerWidget, Button, Text, TextArea, TextBox, ComboBox, CheckBox, _MultiUploader, MultiInput, LabelPane, TitlePane, put, Image, ImageUploader, _TabForm, SVGUploader, RichTextEditor, ThumbnailDndList, _) {
+], function(declare, lang, array, domClass, Dialog, registry, NumberTextBox, _ColorPicker, color, validate, dialog, tools, ContainerWidget, Button, Text, TextArea, TextBox, ComboBox, CheckBox, _MultiUploader, MultiInput, LabelPane, TitlePane, put, Image, ImageUploader, _TabForm, SVGUploader, RichTextEditor, ThumbnailDndList, ckeditor, Editor, _) {
 
 	// make ColorPicker handle null values
 	var ColorPicker = declare(_ColorPicker, {
@@ -273,7 +275,7 @@
 				size: 'Two'
 			}, {
 				name: 'long_description',
-				type: RichTextEditor,
+				type: Editor,
 				label: _('Long description as shown on the App page'),
 				description: _('A more complete description of the App. Shown before installation.'),