does not accept some valid email addresses

Logged In: YES
user_id=1254951
Originator: NO

Can confirm this problem exists. See http://www.uk-poly.net/register.php as an example where plus symbol is not accepted. Unsure of version of XOOPS however.

confirmed.
The "+" sign is allowed in Emai, but You can't registrer in XOOPS 2.3.3 with that.

old code from include/functions.php

function checkEmail($email, $antispam = false)
{
if (!$email || !preg_match("/^[_a-z0-9-]+(.[_a-z0-9-]+)*@[a-z0-9-]+([.][a-z0-9-]+)+$/i", $email)){
return false;
}
if ($antispam) {
$email = str_replace("@", " at ", $email);
$email = str_replace(".", " dot ", $email);
}
return $email;
}

Surgestion for replacementcode
Also checks that there no more that 64 characters before @-sign and no more than 255 after.

function checkEmail($email, $antispam = false)
{
if (!ereg("^[^@]{1,64}@[^@]{1,255}$", $email)) {
}
$email_array = explode("@", $email);
$local_array = explode(".", $email_array[0]);
for ($i = 0; $i < sizeof($local_array); $i++) {
if
(!ereg("^(([A-Za-z0-9!#$%&'*+/=?^_{|}~-][A-Za-z0-9!#$%& ↪'*+/=?^_{|}~.-]{0,63})|(\"[^(\|\")]{0,62}\"))$",
$local_array[$i])) {
return false;
}
}
if (!ereg("^[?[0-9.]+]?$", $email_array[1])) {
$domain_array = explode(".", $email_array[1]);
if (sizeof($domain_array) < 2) {
return false; // Not enough parts to domain
}
for ($i = 0; $i < sizeof($domain_array); $i++) {
if
(!ereg("^(([A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])|
↪([A-Za-z0-9]+))$",
$domain_array[$i])) {
return false;
}
}
}
if ($antispam) {
$email = str_replace("@", " at ", $email);
$email = str_replace(".", " dot ", $email);
}
return $email;
}

Fixed in SVN and waiting for review