
Drupal users who recently upgraded from 6.x.2.10 to 6.x.2.16 noticed that the Views which were using Exposed filters stopped working correctly. The reason for the error was that the Exposed Filter was optional in 6.x.2.10 but not in 6.x.2.16. The "Optional" checkbox no longer existed in the new version. If you are encountering a similar situation in your Drupal site then read on to find the fix.