Manage Events fatal error after upgrading from 5.4 to 5.10
I can see that the getAllPermissions() method is present, so if you're getting a "call to undefined method" error you very likely have either an extension or a customization that's overriding the file &lt;civiroot&gt;/CRM/Event/BAO/Event.php.  

Turn on debugging and backtrace (Administer menu » System Settings » Debugging and Error Handling) and this error should become much more detailed.  If you're not sure how to interpret the backtrace to find your customizations, you can edit your question to include the backtrace and someone will likely be able to help.