Just a little background about the calendar reform. In 1923, the Ecumenical Patriarch held a congress to revise the Church's liturgical calendar, which settled on a compromised New Revised Julian Calendar, where feastdays revolving around Pascha will continue to be calculated according the old Julian Calendar.

In practice, Pascha and all feasts revolving around it, eg Ascension, Pentecost are observed on the same actual date no matter if a church uses the Old or New Calendar. This allows for the observance of the Resurrection with unity among all Orthodox Churches, but different on the majority of the time with the Catholics and Protestants.

In order to bridge the gap with the Catholics and Protestants, the calendar reform also agreed to have all fixed feastdays that were according to the Julian calendar to switch over to be according to the Gregorian calendar without time adjustment. So the Nativity of Christ which was originally observed on December 25 on Julian Calendar and having by 1923 lagged for 13 days, will henceforth be observed on December 25 on the Gregorian Calendar without adjustment. This creates calendar unity with the Catholics, Protestants and the rest of the western secular world, but it creates disunity with those among the Orthodox Churches who still held to the Old Calendar like in Russia, Serbia and Jerusalem where December 25 Julian is celebrated 13 days later on January 7 according to the Gregorian calendar.

Now let us take the example of the repose date of St John Maximovich who was Archbishop of Shanghai and later of San Francisco under the Russian Church Abroad (ROCOR), which uses the Old Calendar. He died after the Calendar Reform of 1923, specifically on July 2, 1966 on the Gregorian calendar. ROCOR designated the Saturday closest to his repose date of June 19 according to the Julian calendar as his feast day, where according to the Old Calendar usage is currently the same as July 2 on the Gregorian calendar. If he would have been reposed or glorified before 1923, then New Calendar churches would have commemorated him on June 19 on the Gregorian calendar without adding 13 days. Since the Julian calendar only lags an additional day with the Gregorian calendar after about every 131 years, in all practicality both the Old and New Calendar churches during our century observes St John's feastday on the same actual day, i.e. July 2 on the Gregorian calendar.

Thus, any newly canonized saints reposed or glorified after 1923 would be observed on the same actual date no matter Old or New Calendar, unless officially promulgated otherwise. Some Orthodox Calendar publishing companies may unintentionally put St John on June 19 on the new calendar based on the assumption that any fixed feasts are carried over from Julian date to Gregorian date without adding 13 days.