Just an FYI for any devs on the list:
I just upgraded my 1.35.2 MW to 1.36.0 via a tarball release and received several "premature access" deprecation warnings from PHP in the process. No fatal errors were thrown, so the upgrade completed successfully. Still, this might be something to look into.
OS Fedora 34
Apache 2.4.46
PHP 7.4.19 (fpm-fcgi)
MariaDB 10.5.10
The following warnings we thrown at the start of running "php update.php":
PHP Deprecated: Premature access to service container [Called from Maintenance::finalSetup in /var/www/gpf/mediawiki-1.36.0/maintenance/includes/Maintenance.php at line 1221] in /var/www/gpf/mediawiki-1.36.0/includes/debug/MWDebug.php on line 376
PHP Deprecated: Premature access to service 'HookContainer' [Called from MediaWiki\MediaWikiServices::getInstance in /var/www/gpf/mediawiki-1.36.0/includes/MediaWikiServices.php at line 252] in /var/www/gpf/mediawiki-1.36.0/includes/debug/MWDebug.php on line 376
PHP Deprecated: Premature access to service 'ObjectFactory' [Called from Wikimedia\Services\ServiceContainer::{closure} in /var/www/gpf/mediawiki-1.36.0/includes/ServiceWiring.php at line 535] in /var/www/gpf/mediawiki-1.36.0/includes/debug/MWDebug.php on line 376
Hope this helps...