Reference
OpenAI's Answer
The primary difference between the Julian and Revised Julian calendars lies in how they handle leap years.
The Julian calendar, established by Julius Caesar in 46 BC, has a simple rule: every year divisible by four is a leap year. This means that a leap day is added every four years, without exceptions.
The Revised Julian calendar, proposed in 1923, includes a more complex leap year rule to improve accuracy. According to this calendar, a year is a leap year if it is divisible by four, except for years that leave a remainder of 200 or 600 when divided by 900, which are not leap years. This makes the Revised Julian calendar more accurate than its predecessor by aligning more closely with the solar year.
In practical terms, the Revised Julian calendar is nearly identical to the Gregorian calendar, which is now widely adopted. Both calendars diverge from the Julian calendar by reducing the frequency of leap years to better approximate the actual time it takes the Earth to orbit the Sun.
For more detailed information, you can visit WorldTimeServer.