public function sanitize_installed_version( $value ) {
		$value = trim( (string) $value );

		if ( (bool) preg_match( '/[^\d\.]/', $value ) ) {
			add_settings_error(
				'soter_installed_version',
				'invalid_soter_installed_version',
				'Installed version can only contain the following characters: 0123456789.'
			);

			return $this->installed_version;
		}

		return $value;
	}