diff --git a/application/config/constants.php b/application/config/constants.php
index 7efb65d2..1e30f6d0 100644
--- a/application/config/constants.php
+++ b/application/config/constants.php
@@ -13,10 +13,10 @@
 | always be used to set the mode correctly.
 |
 */
-define('FILE_READ_MODE', 0644);
-define('FILE_WRITE_MODE', 0666);
-define('DIR_READ_MODE', 0755);
-define('DIR_WRITE_MODE', 0777);
+const FILE_READ_MODE = 0644;
+const FILE_WRITE_MODE = 0666;
+const DIR_READ_MODE = 0755;
+const DIR_WRITE_MODE = 0777;
 
 /*
 |--------------------------------------------------------------------------
@@ -27,14 +27,14 @@ define('DIR_WRITE_MODE', 0777);
 |
 */
 
-define('FOPEN_READ', 'rb');
-define('FOPEN_READ_WRITE', 'r+b');
-define('FOPEN_WRITE_CREATE_DESTRUCTIVE', 'wb'); // truncates existing file data, use with care
-define('FOPEN_READ_WRITE_CREATE_DESTRUCTIVE', 'w+b'); // truncates existing file data, use with care
-define('FOPEN_WRITE_CREATE', 'ab');
-define('FOPEN_READ_WRITE_CREATE', 'a+b');
-define('FOPEN_WRITE_CREATE_STRICT', 'xb');
-define('FOPEN_READ_WRITE_CREATE_STRICT', 'x+b');
+const FOPEN_READ = 'rb';
+const FOPEN_READ_WRITE = 'r+b';
+const FOPEN_WRITE_CREATE_DESTRUCTIVE = 'wb'; // truncates existing file data, use with care
+const FOPEN_READ_WRITE_CREATE_DESTRUCTIVE = 'w+b'; // truncates existing file data, use with care
+const FOPEN_WRITE_CREATE = 'ab';
+const FOPEN_READ_WRITE_CREATE = 'a+b';
+const FOPEN_WRITE_CREATE_STRICT = 'xb';
+const FOPEN_READ_WRITE_CREATE_STRICT = 'x+b';
 
 
 /*
@@ -45,54 +45,54 @@ define('FOPEN_READ_WRITE_CREATE_STRICT', 'x+b');
 | These constants are used globally from the application when handling data.
 |
 */
-define('DB_SLUG_CUSTOMER', 'customer');
-define('DB_SLUG_PROVIDER', 'provider');
-define('DB_SLUG_ADMIN', 'admin');
-define('DB_SLUG_SECRETARY', 'secretary');
+const DB_SLUG_CUSTOMER = 'customer';
+const DB_SLUG_PROVIDER = 'provider';
+const DB_SLUG_ADMIN = 'admin';
+const DB_SLUG_SECRETARY = 'secretary';
 
-define('FILTER_TYPE_ALL', 'all');
-define('FILTER_TYPE_PROVIDER', 'provider');
-define('FILTER_TYPE_SERVICE', 'service');
+const FILTER_TYPE_ALL = 'all';
+const FILTER_TYPE_PROVIDER = 'provider';
+const FILTER_TYPE_SERVICE = 'service';
 
-define('AJAX_SUCCESS', 'SUCCESS');
-define('AJAX_FAILURE', 'FAILURE');
+const AJAX_SUCCESS = 'SUCCESS';
+const AJAX_FAILURE = 'FAILURE';
 
-define('SETTINGS_SYSTEM', 'SETTINGS_SYSTEM');
-define('SETTINGS_USER', 'SETTINGS_USER');
+const SETTINGS_SYSTEM = 'SETTINGS_SYSTEM';
+const SETTINGS_USER = 'SETTINGS_USER';
 
-define('PRIV_VIEW', 1);
-define('PRIV_ADD', 2);
-define('PRIV_EDIT', 4);
-define('PRIV_DELETE', 8);
+const PRIV_VIEW = 1;
+const PRIV_ADD = 2;
+const PRIV_EDIT = 4;
+const PRIV_DELETE = 8;
 
-define('PRIV_APPOINTMENTS', 'appointments');
-define('PRIV_CUSTOMERS', 'customers');
-define('PRIV_SERVICES', 'services');
-define('PRIV_USERS', 'users');
-define('PRIV_SYSTEM_SETTINGS', 'system_settings');
-define('PRIV_USER_SETTINGS', 'user_settings');
-define('PRIV_WEBHOOKS', 'webhooks');
+const PRIV_APPOINTMENTS = 'appointments';
+const PRIV_CUSTOMERS = 'customers';
+const PRIV_SERVICES = 'services';
+const PRIV_USERS = 'users';
+const PRIV_SYSTEM_SETTINGS = 'system_settings';
+const PRIV_USER_SETTINGS = 'user_settings';
+const PRIV_WEBHOOKS = 'webhooks';
 
-define('DATE_FORMAT_DMY', 'DMY');
-define('DATE_FORMAT_MDY', 'MDY');
-define('DATE_FORMAT_YMD', 'YMD');
+const DATE_FORMAT_DMY = 'DMY';
+const DATE_FORMAT_MDY = 'MDY';
+const DATE_FORMAT_YMD = 'YMD';
 
-define('TIME_FORMAT_REGULAR', 'regular');
-define('TIME_FORMAT_MILITARY', 'military');
+const TIME_FORMAT_REGULAR = 'regular';
+const TIME_FORMAT_MILITARY = 'military';
 
-define('MIN_PASSWORD_LENGTH', 7);
-define('MAX_PASSWORD_LENGTH', 100);
-define('ANY_PROVIDER', 'any-provider');
+const MIN_PASSWORD_LENGTH = 7;
+const MAX_PASSWORD_LENGTH = 100;
+const ANY_PROVIDER = 'any-provider';
 
-define('CALENDAR_VIEW_DEFAULT', 'default');
-define('CALENDAR_VIEW_TABLE', 'table');
+const CALENDAR_VIEW_DEFAULT = 'default';
+const CALENDAR_VIEW_TABLE = 'table';
 
-define('AVAILABILITIES_TYPE_FLEXIBLE', 'flexible');
-define('AVAILABILITIES_TYPE_FIXED', 'fixed');
+const AVAILABILITIES_TYPE_FLEXIBLE = 'flexible';
+const AVAILABILITIES_TYPE_FIXED = 'fixed';
 
-define('EVENT_MINIMUM_DURATION', 5); // Minutes
+const EVENT_MINIMUM_DURATION = 5; // Minutes
 
-define('DEFAULT_COMPANY_COLOR', '#ffffff');
+const DEFAULT_COMPANY_COLOR = '#ffffff';
 
 /*
 |--------------------------------------------------------------------------
@@ -103,22 +103,22 @@ define('DEFAULT_COMPANY_COLOR', '#ffffff');
 |
 */
 
-define('WEBHOOK_APPOINTMENT_SAVE', 'appointment_save');
-define('WEBHOOK_APPOINTMENT_DELETE', 'appointment_delete');
-define('WEBHOOK_UNAVAILABILITY_SAVE', 'unavailability_save');
-define('WEBHOOK_UNAVAILABILITY_DELETE', 'unavailability_delete');
-define('WEBHOOK_CUSTOMER_SAVE', 'customer_save');
-define('WEBHOOK_CUSTOMER_DELETE', 'customer_delete');
-define('WEBHOOK_SERVICE_SAVE', 'service_save');
-define('WEBHOOK_SERVICE_DELETE', 'service_delete');
-define('WEBHOOK_SERVICE_CATEGORY_SAVE', 'service_category_save');
-define('WEBHOOK_SERVICE_CATEGORY_DELETE', 'service_category_delete');
-define('WEBHOOK_PROVIDER_SAVE', 'provider_save');
-define('WEBHOOK_PROVIDER_DELETE', 'provider_delete');
-define('WEBHOOK_SECRETARY_SAVE', 'secretary_save');
-define('WEBHOOK_SECRETARY_DELETE', 'secretary_delete');
-define('WEBHOOK_ADMIN_SAVE', 'admin_save');
-define('WEBHOOK_ADMIN_DELETE', 'admin_delete');
+const WEBHOOK_APPOINTMENT_SAVE = 'appointment_save';
+const WEBHOOK_APPOINTMENT_DELETE = 'appointment_delete';
+const WEBHOOK_UNAVAILABILITY_SAVE = 'unavailability_save';
+const WEBHOOK_UNAVAILABILITY_DELETE = 'unavailability_delete';
+const WEBHOOK_CUSTOMER_SAVE = 'customer_save';
+const WEBHOOK_CUSTOMER_DELETE = 'customer_delete';
+const WEBHOOK_SERVICE_SAVE = 'service_save';
+const WEBHOOK_SERVICE_DELETE = 'service_delete';
+const WEBHOOK_SERVICE_CATEGORY_SAVE = 'service_category_save';
+const WEBHOOK_SERVICE_CATEGORY_DELETE = 'service_category_delete';
+const WEBHOOK_PROVIDER_SAVE = 'provider_save';
+const WEBHOOK_PROVIDER_DELETE = 'provider_delete';
+const WEBHOOK_SECRETARY_SAVE = 'secretary_save';
+const WEBHOOK_SECRETARY_DELETE = 'secretary_delete';
+const WEBHOOK_ADMIN_SAVE = 'admin_save';
+const WEBHOOK_ADMIN_DELETE = 'admin_delete';
 
 /* End of file constants.php */
 /* Location: ./application/config/constants.php */