OMP error 3.1.2

[Tue Mar 12 09:39:48.853638 2019] [fcgid:warn] [pid 16753] [client 192.168.31.1:6407] mod_fcgid: stderr: PHP Warning: Declaration of PublicationFormatCategoryGridDataProvider::loadData($request, $filter = NULL) should be compatible with SubmissionFilesCategoryGridDataProvider::loadData() in /home/editorial2/public_html/controllers/grid/catalogEntry/PublicationFormatCategoryGridDataProvider.inc.php on line 19, referer: https://editorial.autonoma.edu.co/index.php/libros/workflow/index/74/1
[Tue Mar 12 09:39:48.903706 2019] [fcgid:warn] [pid 22343] [client 192.168.31.1:6405] mod_fcgid: stderr: PHP Warning: Declaration of AddThisPlugin::register($category, $path) should be compatible with LazyLoadPlugin::register($category, $path, $mainContextId = NULL) in /home/editorial2/public_html/plugins/generic/addThis/AddThisPlugin.inc.php on line 168, referer: https://editorial.autonoma.edu.co/index.php/libros/workflow/index/74/1
[Tue Mar 12 09:39:48.903785 2019] [fcgid:warn] [pid 22343] [client 192.168.31.1:6405] mod_fcgid: stderr: PHP Warning: Declaration of CustomBlockPlugin::getBlockContext() should be compatible with BlockPlugin::getBlockContext($contextId = NULL) in /home/editorial2/public_html/plugins/generic/customBlockManager/CustomBlockPlugin.inc.php on line 134, referer: https://editorial.autonoma.edu.co/index.php/libros/workflow/index/74/1
[Tue Mar 12 09:42:19.627595 2019] [negotiation:error] [pid 24938] [client 192.168.31.1:7082] AH00690: no acceptable variant: /home/editorial2/public_html/index
[Tue Mar 12 09:42:22.131604 2019] [fcgid:warn] [pid 14838] [client 192.168.31.1:7094] mod_fcgid: stderr: PHP Warning: Declaration of RegistrationHandler::validate($request) should be compatible with PKPHandler::validate($requiredContexts = NULL, $request = NULL) in /home/editorial2/public_html/lib/pkp/pages/user/RegistrationHandler.inc.php on line 19

I think all the errors coming from OMP are just warnings. But there is an error related to apache settings there: php - "no acceptable variant" from MultiViews in Apache - Stack Overflow