I received notification that PHP was being updated by my hosting service.  I believe that I went from 7.4 to 8.1.  The community won't load anymore.  I see a fully white screen with a few links.

I see these error messages:

Error: Call to undefined function create_function() (0)
#0 /home/org/public_html/conf_global.php(163): IPB_Firewall::_calculateChecksums(Array, 0)
#1 /home/org/public_html/conf_global.php(135): IPB_Firewall::_doSecurityChecks()
#2 /home/org/public_html/conf_global.php(367): IPB_Firewall::run()
#3 /home/org/public_html/system/Dispatcher/Dispatcher.php(69): require('/home/liafo/pub...')
#4 /home/org/public_html/index.php(13): IPS\_Dispatcher::i()
#5 {main}

I downloaded a new set of files and copied them the relevant directory.  Admin Upgrade loads but it gives me this error: Call to undefined function create_function()

Any idea how to recover from this?  I apparently also don't get support on my plan anymore.  

This is resolved.  I was able to revert the PHP version to 7.4.  I still have to find an upgrade path, but this is resolved for now.

It looks like you have a 3rd party application which is not compatible with PHP 8.1 there. You would need to identify which one it is and report it to the author

I am having the same problem and there are no 3rd party applications installed. Any suggestions?

If you have references to ipb_ firewall inf your conf_global.php file, remove them.