To download from the Qlik site you need to be logged in as a Customer or a Partner. If you are one of these are you don't see the correct download page when logged in you should contact your Partner, or if you are a Partner your Partner Manager at Qlik.
If you are just using the free connectors with Sense Desktop or QlikView PE then you may be a bit stuck.
The links for the latest version and it's documentation are:
Make sure you read the upgrade steps carefully, as it is possible to mess up your installation by overwriting some of the files in your QWC folder on upgrade.
Hope that helps.