The Postmark Messages API has been enhanced to allow users to search for inbound or outbound messages by date, status, and other filtering options. The new API endpoint enables users to search for failed messages and retry them using a new `PUT /messages/inbound/[MessageID]/retry` call. Additionally, the API now supports wildcard domains, allowing users to send messages to multiple subdomains with a single domain record in their DNS settings. This feature is useful for servicing multiple users or development environments with Postmark Inbound processing.