Suggestion: To add an action that checks if a certain email or SMS has been opened by the contact in the last X (specified by the user) days and, like the if/else action, takes them down different paths in the workflow based on whether they HAVE opened the message (i.e. TRUE) or NOT (i.e FALSE). This is an action Active Campaign has (see picture) and is super helpful for sending out reminder emails, creating email campaign automations and more where you want to do different things/send different messages if they did or did not open a previous message.