Hi,
I tried to upgrade and now my site is not working at all anymore. This is the reply from the upgrade in admin:

1.0> Checking for latest version
1.1> Connecting to server: codoforum.com ...
####: Initiating cURL request
1.3> Response: 
Raw: 3.5|codoforum.v.3.5.patch.zip|4b633447062a77d4a0818e3595253bf5 
Latest version is 3.5
File to be downloaded to cache dir: codoforum.v.3.5.patch.zip
1.4> Initiating Download phase 2.0...
Notice: ob_end_flush(): failed to delete and flush buffer. No buffer to delete or flush in /customers/b/9/0/mysite.nl/httpd.www/admin/modules/system/upgrade.php on line 369 2.0> Initiated.
2.1> Downloading the latest version, Please wait...
2.1> File already downloaded :)
Notice: ob_end_flush(): failed to delete and flush buffer. No buffer to delete or flush in /customers/b/9/0/mysite.nl/httpd.www/admin/modules/system/upgrade.php on line 369 3.0> File upgrade process initiating... 
3.1> Files seem writable :) 
 Notice: ob_end_flush(): failed to delete and flush buffer. No buffer to delete or flush in /customers/b/9/0/mysite.nl/httpd.www/admin/modules/system/upgrade.php on line 369 started DU>Unpacking contents 
>Unpacking contents Completed.
>Ungrading schema 
 Notice: Trying to get property of non-object in /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Processors/MySqlProcessor.php on line 13 Notice: Trying to get property of non-object in /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Processors/MySqlProcessor.php on line 13 Notice: Trying to get property of non-object in /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Processors/MySqlProcessor.php on line 13 Notice: Trying to get property of non-object in /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Processors/MySqlProcessor.php on line 13 Fatal error: Cannot redeclare col_exists() (previously declared in /customers/b/9/0/mysite.nl/httpd.www/install/upgrade/3.4.php:39) in /customers/b/9/0/mysite.nl/httpd.www/install/upgrade/3.5.php on line 8

this is the result on my site:

Fatal error: Uncaught exception 'Illuminate\Database\QueryException' with message 'SQLSTATE[42S02]: Base table or view not found: 1146 Table 'mysite_nl.codo_report_types' doesn't exist (SQL: select * from `codo_report_types`)' in /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Connection.php:555 Stack trace: #0 /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Connection.php(283): Illuminate\Database\Connection->run('select * from `...', Array, Object(Closure)) #1 /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Builder.php(1360): Illuminate\Database\Connection->select('select * from `...', Array) #2 /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Builder.php(1350): Illuminate\Database\Query\Builder->runSelect() #3 /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Query/Builder.php(1337): Illuminate\Databas in /customers/b/9/0/mysite.nl/httpd.www/sys/vendor/illuminate/database/Illuminate/Database/Connection.php on line 555

please advise what I can do!!
It seems it's missing some tables...

hope you can help me

You should of backed up your database before trying to upgrade, I'm under the impression latest version 3.51 isn't ready yet...

I found a backup in the cache folder and went back to 3.4. all is well now.