Yesterday The Senate Foreign Relations Committee released this statement on Russia's bombing of Ukraine:

[Emrys]

14. In 2023, Ukraine changed the official celebration of Christmas to December 25th

Ukrainians mark Orthodox Christmas on December 25 in snub to Russia

Many Ukrainians will on Monday celebrate Christmas Day on December 25 for the first time, after the government changed the date from the Orthodox Church observance of January 7 in a snub to Russia. Ukraine passed a law in July moving the celebration to December 25, the day when most of the Christian world marks Christmas.
...
The Orthodox Church of Ukraine, a newly created independent church that held its first service in 2019, has also changed its Christmas date to December 25.

It formally broke away from the Russian Orthodox Church over Moscow's annexation of Crimea in 2014 and its support for separatists in eastern Ukraine.

The political rift has seen priests and even entire parishes swap from one church to another, with the new Orthodox Church of Ukraine growing fast and taking over several Russia-linked church buildings in moves supported by the government.

The historically Russia-linked Ukrainian Orthodox Church, meanwhile, is keeping the January 7 Christmas date. This church claims to have cut ties with Russia because of the war but many Ukrainians view this with scepticism.

The country's third Orthodox denomination, the Ukrainian Greek Catholic Church, will also hold Christmas services on December 25.

https://www.france24.com/en/live-news/20231224-ukrainians-defy-moscow-with-first-dec-25-christmas