XF 2.1 Upgrade Errors on Xenforo 2.1.2

[XnForFanKN]

When upgrading from Xenforo 1.5.24 to Xenforo 2.1.2, I am getting the following error when I start the upgrade:

PHP Fatal error: Array and string offset access syntax with curly braces is no longer supported in /src/vendor/dokuwiki/utf8/utf8.php on line 66

Why would I get this error? This is a newly downloaded copy of the files from Xenforo.com.

Also, after changing the coding to fix the error, I received another error:

PHP Fatal error: Uncaught Error: Unknown named parameter $config in /src/vendor/league/flysystem-eventable-filesystem/src/EventableFilesystem.php:431
Stack trace:
#0 /src/vendor/league/flysystem-eventable-filesystem/src/EventableFilesystem.php(431): call_user_func_array()
#1 /src/vendor/league/flysystem-eventable-filesystem/src/EventableFilesystem.php(395): League\Flysystem\EventableFilesystem\EventableFilesystem->callFilesystemMethod()
#2 /src/vendor/league/flysystem-eventable-filesystem/src/EventableFilesystem.php(128): League\Flysystem\EventableFilesystem\EventableFilesystem->delegateMethodCall()
#3 /src/vendor/league/flysystem/src/MountManager.php(311): League\Flysystem\EventableFilesystem\EventableFilesystem->has()
#4 /src/XF/Util/File.php(724): League\Flysystem\MountManager->has()
#5 /src/XF/Error.php(346): XF\Util\File::installLockExists()
#6 /src/XF/App.php(2193): XF\Error->displayFatalExceptionMessage()
#7 /src/XF.php(171): XF\App->displayFatalExceptionMessage()
#8 [internal function]: XF::handleException()
#9 {main}
thrown in /src/vendor/league/flysystem-eventable-filesystem/src/EventableFilesystem.php on line 431

What would be causing this error? Do I need to correct these errors manually, or is there something else wrong?

Thank you very much for your help.

 

[ENF]

PHP Fatal error: Array and string offset access syntax with curly braces is no longer supported in /src/vendor/dokuwiki/utf8/utf8.php on line 66

This is probably pointing to an issue with your PHP version.
What version of PHP are you using?

 

[briansol]

This is coming from the docuwiki addon. Try disabling that or upgrading it.

 

[ENF]

This is coming from the docuwiki addon. Try disabling that or upgrading it.

This function is a part of the XenForo core package. ../src/vendor/docuwiki (not an addon)
Since they are upgrading from XF 1.x to 2.x, this appears to a be conflict with PHP and not with the Xenforo package itself.