Reminder Book is a simple and practical event management app designed to help users manage various events without any ads or in-app purchases.

Key Features:
D-Day: Easily calculate and set D-Days to keep track of the countdown or the number of days elapsed.
Repeating Events: Add weekly, monthly, or yearly repeating events on the home page, and the app will automatically calculate the next occurrence.
Date Selection: Select a date on the home page to view all the events that are scheduled for that day. It's simple and convenient to use.
Event View: Get a clear and organized list of all the events that have been added to the app.
Widgets: Use various widgets to easily view specific events and daily schedules. The app also supports lock screen widgets.
iCloud Backup: Safely and reliably backup user data to iCloud.