Most Ukrainians are Orthodox Christians. But in July this year, President Volodymyr Zelenskyy signed a bill into law making 25 December the official Christmas holiday as the country adopted the Western, Gregorian calendar.
It should be noted that many Orthodox churches have actually been using 25th December as the date for 100 years now, following the 1923 Council of Constantinople. The choice to shift to the Gregorian date (or rather the Revised Julian date, but it’s the same day as the Gregorian one) is just a shift to align with other Eastern Orthodox patriarchates rather than a departure from Eastern Orthodoxy altogether
It should be noted that many Orthodox churches have actually been using 25th December as the date for 100 years now, following the 1923 Council of Constantinople. The choice to shift to the Gregorian date (or rather the Revised Julian date, but it’s the same day as the Gregorian one) is just a shift to align with other Eastern Orthodox patriarchates rather than a departure from Eastern Orthodoxy altogether