The periodical option (every x minutes) on the Cron expression helper now has the added flexibility to restrict the job to particular days. For example, you can now get the Cron expression for a job that runs every 20 minutes on weekdays only. Leave the day option on "every day" for the same functionality as before.
In addition, an issue that resulted in incorrect results for certain inputs using the time-frame option has been fixed. The util now correctly deals with time-frames such as 3am-2am (a 23 hour period) or time-frames that pass through midnight such as 11pm-2am.