I was trying to update my software to the latest version via the AdminCP, and now I'm getting a 500 Internal Server Error. Can't access the AdminCP.  I tried using constants.php to get into Recovery Mode, but that's not working either. Any ideas?

Never mind, switching back to PHP 7.4 fixed it. 

If you were running PHP 8, often these are third party applications/plugins/themes that are not compatible with PHP 8 or the version of Invision Community you're running. You will want to disable all third-party applications/plugins and switch to an unmodified theme to test. If you're still getting an 500 Internal Server Error, you will need to obtain the server error log entry for this error for further assistance.

Please be aware that while switching back to PHP 7.4 may temporarily resolve your issue, in November, we will start requiring PHP 8, as mentioned here: https://invisioncommunity.com/forums/topic/469486-php8-will-be-the-minimum-version-from-november-2022/