Remind the break and pgsql ;)

switch (Yii::app()->db->driverName)
{
case 'sqlsrv':
case 'dblib':
case 'mssql':
$sSubstringCommand='substring';
break,
default:
$sSubstringCommand='substr';
}

Maybe you can test and make a pull request ?
:)

Thank you Denis! I'll test with this code:
switch (Yii::app()->db->driverName){
case 'sqlsrv':
case 'dblib':
case 'mssql':
case 'mysql':
case 'mysqli':
$sSubstringCommand='substring';
break;
default:
$sSubstringCommand='substr';
}
Is this OK? I'm not on GitHub by the way....

mysqli : not needed
mysql accept substr or substring, then leave substr seems better.

A github account is free ;)

PS : seems substring is know by all SQL server except SQLite :http://sql.sh/fonctions/substring . Maybe use substring directly ?
PS2 : oh no ... pgSQL system need FROM for substring and not for substr ....

updatedb_helper.php, line 1398 altered to:
switch (Yii::app()->db->driverName){
case 'sqlsrv':
case 'dblib':
case 'mssql':
$sSubstringCommand='substring';
break;
default:
$sSubstringCommand='substr';
}
This works OK.
However, in the token table column update statements following this something goes wrong, will be reported separately.

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=15612

Version 2.06+ Build 150729 released