function doInitialUpgrade() {
		$_option = $this->getSlug();
		$options = get_option( 'pressbooks_theme_options_' . $_option, $this->defaults );
		$deprecated = [
			'toc_collapse',
			'accessibility_fontsize',
		];

		foreach ( $options as $key => $value ) {
			if ( in_array( $key, $deprecated, true ) ) {
				unset( $options[ $key ] );
			}
		}

		update_option( 'pressbooks_theme_options_' . $_option, $options );
	}