What is the ruling on a man communicating with his former female colleagues via the Internet for religious benefit and to inquire about their well-being, and is this considered religiously permissible?

A man's conversation with a woman online is fraught with risks and feared to cause fitnah, because excessive conversation can lead to the attachment of hearts. Therefore, it is not advisable to continue speaking with a woman except out of necessity and to the extent of that necessity. If either party feels an inclination towards the other, the relationship must be severed immediately.