Salesforce: Manage Task Notifications

In Winter '15 release, Salesforce introduce a change in Task notification to let user manage their own email notification. This is enabled by default.

Before Winter '15 release, when user create a Task, there is a checkbox Send Notification Email, if Task is assigned by other user, user who receive Task assigned do not have control to get the email notification or not.

Before Winter '15:

After Winter '15:

notice Send Notification Email is no longer exist

Admin able to deactivate this feature by navigate to:
- Setup | Customize | Activities | Activity Settings
- Deselect Enable User Control over Task Assignment Notifications
- Submit
Deactivate this restore like before Winter '15 release.

When this feature enabled, user can control Task email notification from:
- My Settings | Calendar & Reminders | Reminders & Alerts 
- In Events and Tasks section, look for option Email me when someone assigns me a task
This option is enabled by default, uncheck this will stop user to get any email when task assigned to the user.


Known issue:
"Enable Activity Reminders" in Setup | Customize | Activities | Activity Settings, must be enable, otherwise user will not see "Reminders & Alerts" under Calendar & Reminders, so cannot set option for "Email me when someone assigns me a task"


Reference:
Why I do not see the "Email me when someone assigns me a task" option under my Settings?