Thanks for the hint, I was on 5.3
After updating to 5.6, I got massive error codes like this in my backend:
Strict Standards: call_user_func_array() expects parameter 1 to be a valid callback, non-static method wf_mm::init() should not be called statically in /www/htdocs/w011b9e4/website2014/wp-includes/plugin.php on line 496
Strict Standards: Non-static method wf_mm::default_settings() should not be called statically in /www/htdocs/w011b9e4/website2014/wp-content/plugins/5sec-maintenance-mode/5sec-maintenance-mode.php on line 30
Strict Standards: Non-static method wf_mm::generate_access_token() should not be called statically in /www/htdocs/w011b9e4/website2014/wp-content/plugins/5sec-maintenance-mode/5sec-maintenance-mode.php on line 300
Strict Standards: Accessing static property WPOCore_Settings::$options_page_hook as non static in /www/htdocs/w011b9e4/website2014/wp-content/plugins/wpovernight-sidekick/includes/wpo-core-settings.php on line 262
Strict Standards: call_user_func_array() expects parameter 1 to be a valid callback, non-static method wf_mm::admin_menu() should not be called statically in /www/htdocs/w011b9e4/website2014/wp-includes/plugin.php on line 496
Strict Standards: call_user_func_array() expects parameter 1 to be a valid callback, non-static method wf_mm::register_settings() should not be called statically in /www/htdocs/w011b9e4/website2014/wp-includes/plugin.php on line 496
Strict Standards: Accessing static property WPOCore_Settings::$options_page_hook as non static in /www/htdocs/w011b9e4/website2014/wp-content/plugins/wpovernight-sidekick/wpovernight-sidekick.php on line 73
Strict Standards: call_user_func_array() expects parameter 1 to be a valid callback, non-static method wf_mm::admin_head() should not be called statically in /www/htdocs/w011b9e4/website2014/wp-includes/plugin.php on line 496
I only updated YOP, nothing else. And when I deactivate YOP, there are no errors any more.
Also, while I could translate the Vote button, the rest stays in english: https://www.evernote.com/shard/s86/sh/0af4a064-41a0-4022-b7b0-7c1d5c33578a/48fe3b7ae62f53bfbe91b52fdf36ce70/deep/0/contentmarketing.ch—Blog.png
Any Help here?
Thanks a lot!!