Conclave can begin before March 15th, but this very much depends on the Congregation of Cardinals, electors and non electors, who will only be convoked to their first meeting as of March 1st. And individual cardinals can decide not to participate in conclave on health grounds or for other serious reasons, but must communicate their non-participation to the Holy See. Moreover, anyone involved in the Conclave, from ushers to technicians and secretaries, will be bound to an oath of secrecy. Should they, directly or indirectly, receive information regarding the papal election and reveal this to anyone outside of conclave, they will incur excommunication latae sententiae, as opposed to the former ‘severe penalties’ to have been decided by the future Pope.
These in essence are the main changes made to the norms governing the period of the Vacant See and papal election as laid down in the Motu Poprio promulgated Monday by Pope Benedict XVI and presented to press by the deputy-camerlegno, Bishop Luigi Celata.
Conclave in Sistine Chapel