Hi out there,
update from 2.9 to 2.16 went either via one-click and via SSH wrong (…and copying the error from Putty was a mess for a newbie like me, so I MANUALLY post this error 
…)
php /mnt/web001/d3/98/blablabla/htdocs/Piwik_02/console core:update
leads to Database Update required…from 2.13.1 to 2.16.0…The following plugins will be updated: LanguagesManager…be patient…
ends up in
PHP Fatal error: Class 'Piwik_plugin' not found in /mnt/web001/d3/98/blablbla/htdocs/Piwik_02/plugins/ExampleUI/ExampleUI.php on line 27 Status: 500 Internal Server Errror X-Powered-By: PHP/5.6.19
Again: I manually added this code, not copied it via select and CTRL+V.
Any help?