Methods with the same name as their class will not be constructors in a future version of PHP; Smarty has a deprecated constructor 
in '/home/users/k1042_1067/www/upgrade/pistat/libs/Smarty/Smarty.class.php' at the line 64

#0  Piwik_ErrorHandler(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/Smarty.php:16]
#1  require_once(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/Smarty.php:16]
#2  require_once(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/Loader.php:71]
#3  Piwik_Loader::loadClass(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/Loader.php:108]
#4  Piwik_Loader::autoload(...) called at [:]
#5  spl_autoload_call(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/View.php:38]
#6  Piwik_View->__construct(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/View.php:199]
#7  Piwik_View::clearCompiledTemplates(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/Piwik.php:135]
#8  Piwik::deleteAllCacheOnUpdate(...) called at [/home/users/k1042_1067/www/upgrade/pistat/plugins/Installation/Controller.php:75]
#9  Piwik_Installation_Controller->welcome(...) called at [/home/users/k1042_1067/www/upgrade/pistat/plugins/Installation/Installation.php:76]
#10  Piwik_Installation->dispatch(...) called at [/home/users/k1042_1067/www/upgrade/pistat/libs/Event/Dispatcher.php:284]
#11  Event_Dispatcher->postNotification(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/PluginsManager.php:722]
#12  Piwik_PostEvent(...) called at [/home/users/k1042_1067/www/upgrade/pistat/core/FrontController.php:279]
#13  Piwik_FrontController->init(...) called at [/home/users/k1042_1067/www/upgrade/pistat/index.php:51]