Starting in 2018, the bishops of England and Wales have switched from the commercial to the religious calendar for the feasts of the Epiphany and the Ascension. For the Epiphany, this has the following effect:

2018: moved from 7 January (the first Sunday after 1 January) to 7 January (Saturday the 6th, transferred to the Sunday).

2019: moved from 6 January (the first Sunday after 1 January) to 6 January.

2020: moved from 5 January (the first Sunday after 1 January) to 5 January (Monday the 6th, transferred to the Sunday).

2021: moved from 3 January (the first Sunday after 1 January) to 6 January.

To summarize: the first time you see any difference will be in 2021. But the change is already there in Universalis, and if you are bored or curious, you can use Universalis to look at the calendar for 2021 and see it in action.