Ideal work organization is to have your employees or team members come to work early in the morning, open Redmine or the e-mail client, a list of tasks created for them for the current day awaits them, and they start to work, task by task, promptly updating Redmine, either directly or through third-party applications. Luckily, Redmine can get you closer to this scenario by providing issues summary e-mails.
You need server administrator access with access to cron jobs or scheduled tasks.
You need a test user in Redmine for which you can read its e-mail, and tasks assigned for that user due within next 5 days.
First, we are going to test the rake task for a reminder script: