Do you mean function_exists( 'acf_get_setting' )
?
Since I do not need the version number but the information whether the installed ACF plugin is the free version or the PRO version I built that code:
$is_acf_free = $is_acf_pro = false;
if ( class_exists( 'acf' ) {
if ( defined( 'ACF_PRO' ) ) {
$is_acf_pro = true;
} else {
$is_acf_free = true;
}
}