Version 2.2 of the Booking Management Add-on plugin for Cab Grid Pro introduces a booking reminder feature. This automates the process of sending reminders to customers ahead of their scheduled pickup or return. Up to two reminders can be sent, each at different intervals ahead of bookings. Reminders can be delivered by email or (if Cab Grid Pro v5 is installed) via SMS text message to the customer’s mobile phone.
Configuring Reminders
Reminder configuration is found under the SETTINGS sub-tab of the Booking Management Add-on’s admin page within WordPress. 
Send 1st/2nd Reminder
Each reminder has 3 properties:
- The period (in hours) ahead of the booking when the reminder will be sent
- An option to send the reminder to the customer via email
- An option to send the reminder to the customer via SMS text message (requires Cab Grid Pro v5)
In each of the Hour(s) fields enter the number of hours ahead of the booking to send the reminder. This field accepts only whole numbers. If an Hour(s) box is empty or zero, no reminder will be sent. Example: if Hour(s) is set to two, WordPress will continually look for bookings with a pickup time two hours hence. To send the reminder to the customer by email, insure the checkbox next to ‘Email’ is ticked. To send the reminder to the customer by SMS text message, tick the box next to ‘SMS Text Message’. Text messages are only sent if Twilio is properly configured in the Cab Grid Pro OPTIONS panel. Please note, reminders may not be sent at the exact time scheduled, but will usually be sent up to an hour either side of the scheduled time. So, for a 2-hour reminder, the message will be sent between 1 and 3 hours ahead of the booking. For example, if a booking is scheduled for 12pm with a 2 hour reminder, the reminder message will be sent some time between 9am and 11am, as close to 10am as possible. Return Reminders Customers will also be sent a reminder ahead of any return journey according to the schedule.
Reminder Message
Cab Grid will automatically generate a reminder message, but if a customised message is entered, the customer will receive the custom message instead. The Reminder Message text box accepts text-substitution syntax allowing booking data to be included in the reminder message. From v2.2.4 of the booking management add-on there are also text-substitutions specific to reminder messages that allow the details of a particular leg of a journey to be substituted. For example, the ///legDate/// placeholder will substitute the outbound journey date and time for the outbound leg reminders, and the return date & time for the return leg reminders. Reminder messages sent via email will be prefixed with a salutation (Hi first-name,) and postfixed with a sign off (Kind Regards, Blog-name).
Save Changes
Once reminder configuration is complete, click SAVE CHANGES at the bottom of the page to insure the configuration is saved. Any bookings meeting the reminder configuration criteria will now receive reminder messages.
Notes/Troubleshooting
Reminders are sent using WordPress’s Scheduled Tasks function. This function can be unreliable and/or disabled through a command entered into the wp_config.php file: define('DISABLE_WP_CRON', true);. There are several reasons to disable the WordPress Scheduler. For example, if your site uses a cache, tasks may not get triggered properly or in a timely fashion.
To examine and trigger WordPress’s scheduled tasks, you might want to install a plugin such as Advanced Cron Manager. The booking reminder event is called cabGridBookingsSendReminders.
Solution: Define your own schedule on your web server (using crontab) for a more reliable solution. This will insure the schedule you set in the Booking Management Add-on Settings tab is executed.
Depending on the kind of hosting you have, you may have access to define schedules directly on your web server. This means the server takes care of the schedule directly based on its own date and time settings, without the need for WordPress. Many hosting control panels (like CPanel or Plesk) provide a user interface where tasks can be scheduled, or tasks can be scheduled directly from the command line.
The important thing is that the wp-cron.php is called. Here is an example setting a 5 minute interval via the command line:
*/5 * * * * cd /home/dave/replace-this.com/public; php -q wp-cron.php >/dev/null 2>&1
