qtranslate x after update/migrate crash site

Hi,

Im not a web developer, im trying to solve this at my end,
the site originally 4.9.x version, after the update, there are some other error
and also saying about the old qtranslate x i have is no longer workable,

so i follow some side guide to do the update and changes, now i have come to this

Fatal error: Call to undefined function qtrans_getLanguage() in /home/w22qjcd488ig/new.celergenchina.com/wp-content/themes/celergen/functions.php on line 249

from line 249
/**
* Convert float number to format based on the locale.
*
* @since 2.3.0
*
* @global WP_Locale $wp_locale
*
* @param float $number The number to convert based on locale.
* @param int $decimals Optional. Precision of the number of decimal places. Default 0.
* @return string Converted number in string format.
*/
function number_format_i18n( $number, $decimals = 0 ) {
global $wp_locale;

if ( isset( $wp_locale ) ) {
$formatted = number_format( $number, absint( $decimals ), $wp_locale->number_format[‘decimal_point’], $wp_locale->number_format[‘thousands_sep’] );
} else {
$formatted = number_format( $number, absint( $decimals ) );
}

/**
* Filters the number formatted based on the locale.
*
* @since 2.8.0
* @since 4.9.0 The $number and $decimals parameters were added.
*
* @param string $formatted Converted number in string format.
* @param float $number The number to convert based on locale.
* @param int $decimals Precision of the number of decimal places.
*/
return apply_filters( ‘number_format_i18n’, $formatted, $number, $decimals );
}

to line 281

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