The admission of female serves in 1994 by the Congregation for Divine Worship does not have retroactive effect upon celebrations according to the old Missal of 1962. The papal commission Ecclesia Dei responsible in such matters confirmed this today. Only male servers may be used at celebrations of the “old Mass.” A written response of the commission from May to such a question from Great Britain had been disseminated on internet previously.
The Vatican authority referred to a directive on the old Latin Mass which was published the middle of May. According to this directive, liturgical decrees issued since 1962 which are not compatible with the liturgical books then in use are not binding on Tridentine celebrations.
In 2007 Pope Benedict XVI readmitted the rite, which was superseded worldwide in 1970, the “extraordinary form.” The “modern” celebration according to the Missal of Pope Paul VI (1963-1978) remains the normal form.
Source: KAP, tr. awr.