Please follow the below instructions to deploy the Citrix Web Plugin from your Web Interface. I have chosen to use version 12.1 and I find it to be the most stable.
Citrix Web Client Plugin
1. Copy CitrixOnlinePluginWeb.exe to C:\Program Files (x86)\Citrix\Web Interface\5.4.0\Clients\Windows
2. Setup your web interface to deploy the client. You can refer to the images below under the section for deploying the java client.
3. Edit the file c:\inetpub\wwwroot\<SiteName>\XenApp\conf\WebInterface.conf. Uncomment the line about clientIcawin32 as below
1. Copy the Java client to C:\Program Files (x86)\Citrix\Web Interface\5.4.0\Clients\Java. You can get the files from the Citrix Receiver and Plug-ins\Java of the XenApp 6.5 DVD.
2. Enabe the setting on your web interface under client deployment and your done.