This is big. The rules even after Vatican Council II and the Novus Ordo always maintained that the offices of lector and acolyte were to be filled by males. The conciliar church then allowed the functions of these offices (not the offices themselves) to be filled by females. They did not allow females to fill the offices themselves as it never would have been accepted at the time. These offices are what replaced some of the functions of minor orders in the Pre-VCII Church and were always considered part of the priesthood and allowed step by step to those on their way to priesthood. This is yet another example of the conciliar Church making exceptions to assure the faithful the “rules” are still in place and then later dispensing with the “rules” all together.

In short this act violates over a thousand years of Tradition and Catholic teaching and is an overt power play to lay the foundation for women’s ordination. If you recall, the women deaconess issue is again up for “study” at the order of Francis as he did not like the results of the previous two studies which found its an impossibility. This allowing of women into the offices of lector and acolyte are most assuredly a stealth step to lay the groundwork for women deacons and beyond. For one of the arguments against women deacons is that the offices of acolyte and lector were limited to men only throughout the history of the Church. 

See story here: https://www.vaticannews.va/en/pope/news/2021-01/pope-francis-opens-ministries-lector-acolyte-women.html