Regarding YaBB SE password encryption
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For those upgrading from a version of YaBB greater than 1.5 a password seed was introduced to encrypt passwords.
This will have to be undone and the following code will do this the next time the user logs in.

open the following file
/member.php

look for the following code around line 67
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if ($user['password']!=md5($password)) {  // check password
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you will need to add the following code above it which will deal with the YaBB passwords.

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function yabb_md5($data, $key)
{
	if (strlen($key) > 64)
		$key = pack('H*', md5($key));
	$key  = str_pad($key, 64, chr(0x00));

	$k_ipad = $key ^ str_repeat(chr(0x36), 64);
	$k_opad = $key ^ str_repeat(chr(0x5c), 64);

	return md5($k_opad . pack('H*', md5($k_ipad . $data)));
}
if ($user['password'] == yabb_md5($password, strtolower($username)))
{ // we have a YaBB SE style password
	$user['password'] = md5($password);
	$DB_site->query("UPDATE user SET password = '$user[password]' WHERE userid = $user[userid]");
}
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You should now save and upload your new member.php