Istanbul and Sofia Time Zone Comparison
The distance between Istanbul and Sofia is felt not just in kilometers, but in time zones too. Istanbul and Sofia sit on different continents, in noticeably different time zones, and at least one of them observes daylight saving time.
Because Istanbul and/or Sofia observe daylight saving time for part of the year, the gap between them isn't fixed — it ranges between 0 and 1 hours depending on the season.
With such a small gap, scheduling a call between Istanbul and Sofia is easy — a normal business-hours slot works for both sides on the same calendar day.