Astra_Theme_Extension::setup()

		public function setup() {

			if ( ! defined( 'ASTRA_THEME_VERSION' ) ) {
				return;
			}
			require_once ASTRA_EXT_DIR . 'classes/class-astra-icons.php';

			if ( version_compare( ASTRA_THEME_VERSION, '3.1.0', '>=' ) ) {
				self::$switch_control   = 'ast-toggle-control';
				self::$group_control    = 'ast-color-group';
				self::$selector_control = 'ast-selector';
			} else {
				self::$switch_control   = 'checkbox';
				self::$group_control    = 'ast-settings-group';
				self::$selector_control = 'select';
			}

			require_once ASTRA_EXT_DIR . 'classes/class-astra-addon-builder-loader.php';

			/**
			 * Load deprecated filters.
			 */
			require_once ASTRA_EXT_DIR . 'classes/deprecated/deprecated-filters.php';

			/**
			 * Load deprecated actions.
			 */
			require_once ASTRA_EXT_DIR . 'classes/deprecated/deprecated-actions.php';

			require_once ASTRA_EXT_DIR . 'classes/astra-common-functions.php';
			require_once ASTRA_EXT_DIR . 'classes/class-astra-addon-update-filter-function.php';

			require_once ASTRA_EXT_DIR . 'classes/astra-common-dynamic-css.php';

			if ( function_exists( 'astra_addon_filesystem' ) ) {
				require_once ASTRA_EXT_DIR . 'classes/cache/class-astra-cache-base.php';
				require_once ASTRA_EXT_DIR . 'classes/cache/class-astra-cache.php';
			}

			require_once ASTRA_EXT_DIR . 'classes/class-astra-minify.php';

			if ( function_exists( 'astra_addon_filesystem' ) ) {
				require_once ASTRA_EXT_DIR . 'classes/cache/class-astra-addon-cache.php';
			}
			require_once ASTRA_EXT_DIR . 'classes/class-astra-ext-model.php';

		}