The Catholic Encyclopedia entry on excommunication (from 1908) says an excommunicated person can’t participate in any liturgies, i.e. he can’t even be present. The CIC only says he can’t minister or administer the sacraments. Is the CE out of date or is the CIC not giving all applicable law?
The old Catholic Encyclopedia, while a good source to start with for certain things, is out of date.
According to the law currently in force, an excommunicated person is not excluded from attending Holy Mass. In fact she is obliged to attend Mass on Sundays and Holy Days just like everyone else.
She may not, however, receive Holy Communion. And depending on the reason for the excommunication and the faculties of the confessor, she may not receive sacramental absolution until the censure is lifted… except in danger of death.
We no longer have the category of excommunicate who is also vitandus, to be avoided, shunned. That was rarely imposed and was done away with in the 1983 Code. There was also, once, a tolerandus category I believe. I can’t help of thinking of Card. Kasper’s odd solution for the divorced and civilly remarried, to be seen as “tolerated but not accepted” insofar as Communion is concerned. How odd.
A handy resource is Dr. Peter’s book HERE