I have (had) a working installation 1.9.12 installation that I had extensively customized, so I'd rather not just reinstall. What triggered the error was upgrading my server from Ubuntu 14.04 LTS to 16.04 LTS. This included an upgrade to php7. After the upgrade my other sites (a Wordpress and a Limesurvey installation) work just fine, but all the pages in my osticket installation come back blank. I'm showing the following PHP errors in my apache error log:
[Tue Feb 21 14:56:56.020975 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TicketModel::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.user.php on line 36
[Tue Feb 21 14:56:56.021038 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of User::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.user.php on line 161
[Tue Feb 21 14:56:56.021098 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of Organization::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.organization.php on line 0
[Tue Feb 21 14:56:56.021379 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicForm::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021419 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormField::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021440 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormField::save() should be compatible with VerySimpleModel::save($refetch = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021462 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormEntry::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021542 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormEntryAnswer::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021567 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of SelectionField::getWidget() should be compatible with FormField::getWidget($widgetClass = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021582 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TypeaheadSelectionWidget::render($how) should be compatible with ChoicesWidget::render($mode = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021642 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicList::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.list.php on line 132
[Tue Feb 21 14:56:56.021666 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicListItem::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.list.php on line 456
[Tue Feb 21 14:56:56.021683 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TicketStatus::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.list.php on line 779
[Tue Feb 21 14:56:56.021694 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TicketStatus::create($ht) should be compatible with VerySimpleModel::create($ht = false) in /var/www/support/include/class.list.php on line 779
[Tue Feb 21 14:56:56.022205 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of RandomSequence::save() should be compatible with VerySimpleModel::save($refetch = false) in /var/www/support/include/class.sequence.php on line 0
[Tue Feb 21 14:56:56.022267 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Fatal error: Cannot declare class Error, because the name is already in use in /var/www/support/include/class.error.php on line 0
[Tue Feb 21 14:56:56.020975 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TicketModel::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.user.php on line 36
[Tue Feb 21 14:56:56.021038 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of User::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.user.php on line 161
[Tue Feb 21 14:56:56.021098 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of Organization::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.organization.php on line 0
[Tue Feb 21 14:56:56.021379 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicForm::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021419 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormField::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021440 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormField::save() should be compatible with VerySimpleModel::save($refetch = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021462 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormEntry::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021542 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicFormEntryAnswer::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021567 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of SelectionField::getWidget() should be compatible with FormField::getWidget($widgetClass = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021582 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TypeaheadSelectionWidget::render($how) should be compatible with ChoicesWidget::render($mode = false) in /var/www/support/include/class.dynamic_forms.php on line 0
[Tue Feb 21 14:56:56.021642 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicList::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.list.php on line 132
[Tue Feb 21 14:56:56.021666 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of DynamicListItem::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.list.php on line 456
[Tue Feb 21 14:56:56.021683 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TicketStatus::delete() should be compatible with VerySimpleModel::delete($pk = false) in /var/www/support/include/class.list.php on line 779
[Tue Feb 21 14:56:56.021694 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of TicketStatus::create($ht) should be compatible with VerySimpleModel::create($ht = false) in /var/www/support/include/class.list.php on line 779
[Tue Feb 21 14:56:56.022205 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Warning: Declaration of RandomSequence::save() should be compatible with VerySimpleModel::save($refetch = false) in /var/www/support/include/class.sequence.php on line 0
[Tue Feb 21 14:56:56.022267 2017] [:error] [pid 3714] [client xx.xx.xx.xx:53474] PHP Fatal error: Cannot declare class Error, because the name is already in use in /var/www/support/include/class.error.php on line 0