Updated from version 5.3 to 5.4 and receiving Puc/v5p4/Autoloader.php not found
The file exists on the server, but a Wordpress error log is created :
Permissions over those files are: 0644
Hosting is a Godaddy shared plan
Same here, had to rollback to 5.3
If the file exists but you're still getting the same error, that's probably not an issue with PUC but the server/PHP. On the other hand, if it only shows up once, when upgrading to PUC 5.4, then it could potentially be a PUC issue.
The issue is very strange, I never had problems upgrading PUC before...
I think this might be some hosting/caching/synchronizing/composer issue. Eventually it worked for me, but needed a long time and many syncs. I don't know what happened...