Android to Android
If you are using Google Calendar, you don't need to do anything in particular, and if you have the same account, it will be migrated automatically.
LOCAL calendars
1. Select "Data backup/Restore" in the settings screen to output the backup data, and then transfer the backup data to your new device by email or your preferred method.
2. On a new device, download the backup data you just transferred and save it on the device.
3. On your new device, download and open this app. Open "Data backup/Restore" from the settings screen, tap the "Restore backup data" button, and select the backup data you transferred.
Android to iPhone
If you are using the in-app calendar, it will not automatically link to your iPhone.
If you were using Google Calendar, you can add Google Calendar to the iPhone version of the app and use it on your iPhone as is.
How to add Google Calendar
・Open the "Settings" app on your iPhone
・Tap "Calendar" → "Accounts", tap "Add Account" at the bottom, select "Google", log in with the Google account you want to use, and turn on the calendar item
・Open the Simple Calendar app, go to "Display Settings" on the settings screen, and turn on Google Calendar
That's all there is to it. If it doesn't work, please contact us from the top right button.