What is the ruling on communicating via messages between a suitor and his fiancée during her waiting period (iddah), and is it permissible to marry her after her consent during the iddah?

It is not permissible to explicitly propose to a woman undergoing her 'iddah (waiting period), whether she is observing it due to divorce or widowhood, according to the consensus of Muslims. However, marrying her after her 'iddah has expired is valid, even if the explicit proposal was made during the 'iddah out of ignorance of the ruling.