The Grace Period for WebCenter Portal (WCP) Patch Set 11.1.1.6.x just ended (April 2014) and therefore WCP 11.1.1.6.x has fallen out of Error Correction. This means new patches (error correction) for WCP 11.1.1.6.x will no longer be provided. However, you can still download and install existing WCP 11.1.1.6.x patches. Customers are encouraged to update to the latest Patch Set/Bundle Patch, which at the time of this writing was WCP 11.1.1.8.3. See Error Correction Support Dates for Oracle Fusion Middleware 11g (11.1.1/11.1.2) (Doc ID 1290894.1).
Oracle provides bug fixes for products as part of Premier and Extended Support (but not Sustaining Support). Error Correction explains the methods that are used to deliver bug fixes and some of the policies regarding those methods. The Error Correction Policy describes details about how Oracle delivers error corrections within the life of those releases. This includes policies on how long we will create new fixes for older forms of patch delivery such as patch sets and bundle patches.
See The Importance of Staying Current on the Latest Product Releases and Patches blog entry for more detailed information on the Error Correction Policy and Grace Periods.