There is a Calendar or Task List plugin alert with hour?

Hello,

We used openfire (3.7) and spark (3.6.4) in our company.

In order to ameliorate the functions of this system we search a plugin to have alert like outlook for our Task or Appointment ?

The Task List is good but we have only the alert on login in spark, but it could be intesresting to choose the hour of he alert ?

Do you have any idea how we could do that ?

thanks for all