OPPO mobile phone can check previous calendars, such as 1954.4. 19.

ColorOS 6 and above: open the calendar app > click the ":"icon in the upper right corner > Settings to personalize your calendar.

1, week start date: select one day from Monday to Sunday as the start date.

2. Display legal holidays: select whether to display legal holidays.

3. Display contact's birthday: select whether to display the contact's birthday.

4. Display China Gregorian calendar: select whether to display China Gregorian calendar.

5. Display holiday information: after opening, display holiday information in the schedule area.

6. Import the schedule determined by Breeno: including train tickets, movie tickets, hotels, credit cards, loan bills, etc. , can be opened or closed separately.

7. Import the schedule file: You can import the schedule file into the calendar.

8. Personalized reminder time: click the default reminder time to set the whole day schedule, birthday/anniversary/countdown day schedule and reminder time.

9. Set time zone: After the time zone priority option is turned on, you can set the time zone yourself. When opened, the date and time of the schedule are always displayed in the selected time zone first. If off, the time will be displayed according to the current time zone.

This answer applies to all OPPO models.