The Ukrainian Greek Catholic Church (UGCC) announced Monday that it is switching its fixed-date religious celebrations to match the Gregorian calendar used by the Church in the West.

Ukrainian Catholics have been among the few remaining sects under the papacy to celebrate holidays according to the Julian calendar, which celebrates Christmas on Jan. 7 and Epiphany on Jan. 19. The Russian Orthodox Church and other Eastern Churches under the Patriarchate of Moscow follow the Julian calendar.

Now, Catholics in Ukraine will celebrate feasts on the same dates as Catholics in the U.S. and other Western nations, meaning Christmas will be observed on Dec. 25 and Epiphany on Jan. 6.

The change will take place at the beginning of the Ukrainian Catholic Church’s liturgical year, Sept. 1, 2023.

The head of the UGCC, Major Archbishop Sviatoslav Shevchuk of Kyiv-Galicia, said that the decision was made “taking into account the numerous requests of the faithful and having conducted prior consultations with the clergy and monastics of our Church about the urgent need to reform the liturgical calendar of the UGCC in Ukraine.”

Shevchuk clarified that only holidays that occur on a fixed date every year, such as Christmas, will now be celebrated on the same days as in the West.

Holidays that move from year to year, such as Easter, will continue for the time being to be celebrated in the old style.

According to the release, there is an ongoing dialogue between the Roman and Greek Catholic Churches to settle on a new arrangement for the two to celebrate Easter on the same day. The two Churches hope to be in agreement in time for the 1,700th anniversary of the Council of Nicaea in 2025.

“In preparation for this anniversary, collaborative work is underway in a dialogue between Rome and Constantinople on a renewed Paschalia, according to which all Christians will celebrate Easter on the same day,” the statement said.

Vatican News reported that Shevchuk said that until the Russian invasion of Ukraine, Ukrainian Greek Catholics were divided on whether to make the change, but now more than 90% of Ukrainian Greek Catholics support moving from the Julian calendar and its associations with Russia.

“The desire and need for the calendar reform were much more potent than we could have hoped, and this is good news,” Shevchuk said.

Even though the switch received broad support, the Ukrainian Church will allow individual parishes to continue celebrating feasts according to the Julian calendar if they “feel they are not yet ready for such a step” and obtain special permission from their bishop. This exception will remain possible until 2025, by which point the UGCC wants all parishes to follow the Gregorian calendar.