Admin screen blank after upgrading from v7.4 to 7.5 and loading new language pack


I’ve just upgraded from v7.4 to V 7.5 using upgrade package + upgrade wizard from admin.
Everything went well, except that at the end of the automatic upgrade process ( at point 14/15 of the process I did not see the “Done” button, only the report.
I just went back to the admin menu and checked that version was 7.5 and assumed everything went well.

After checking a few pages to see if everything was OK, I went back to admin page and was able to load a new language pack (french) via admin.

After reconnecting in order to check if language pack worked, I’ve noticed a blank page.

I have the error :
Parse error: syntax error, unexpected ‘[’ in /home/www/lu*****h/c****crm/modules/AOR_Reports/AOR_Report.php on line 215

( note I have added the ‘*’ in the error message above).

It looks like the similar issue has been reported in thread #27609.

What should I do ? I have tried to change the AOR_Report.php file using the latest git hub file without succes, the same error appeared ( on line 175 this time).

note : the line is : public function buildMultiGroupReport($offset = -1, $links = true, $level = 2, $path = []) {

Thank you for your help.