If you have access to your files via ftp, you should be able to upgrade WordPress manually. According to WordPress.org, you can do so by swapping out a few folders and files: Step 1: Replace WordPress files Get the latest WordPress zip (or tar.gz) file. Unpack the zip file that you downloaded. Deactivate plugins. Delete … Read more
This is just a guess, mind you, but it’s still worth a shot. First, turn on debug mode and see if there’s any glaring errors when trying to view your content. If not (and I’m thinking there won’t be, but I would feel quite silly if there were errors pointing to the issue), then roll … Read more
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Don’t use the update now button, use a full on download of the core WP – http://wordpress.org/download/ – and then make sure you flush any cache you’ve got running. Do you have memcached or APC or xcache? Purge that. Plugins ditto. I saw that on one of my sites where my server’s object cache hung … Read more
Softaculous doesnt configure anything in WordPress which would stop a Manual Upgrade. You can contact the support team and they should help you. To test your claim I just upgraded my Blog which was installed by Softaculous and it is working. You should check for the PHP error logs as well.
I don’t think the database schema ever changes so drastically that the versions of wordpress on box 2 + 3 would be prevented from reading from the DB after you’ve updated on box 1, however it depends what version you are upgrading from. Why not set a similar environment locally and test upgrading site 1, … Read more
You should probably upgrade one step at a time from one version to the next. All the code of all the versions are listed at the http://wordpress.org site. It will be a long process but the best to ensure proper upgrades. You can try to make it faster by skipping several versions at each step, … Read more
Most of the time any changes that need to be done on upgrade are database related. Core files can be freely swapped pretty much. WP keeps track of this by comparing db_version option (stored in database) against the current value (from core files) on admin load. If there is mismatch it runs the upgrade routine … Read more
Delete everything but wp-content and wp-config.php, copy the fresh installation into the directory. On upgrading WordPress will use the database to see what should be done, not the files. Not all files are deleted automatically, because some of them might still be used by outdated plugins or external scripts (the old feed files are good … Read more
The featured image itself– the actual .jpg, or .png, most likely– is saved to wp-content/uploads with primary image data saved to $wpdb->posts as an attachment post type. Additional relevant data for the image is saved in $wpdb->postmeta. What makes an image “featured” or not is an entry in $wpdb->postmeta under the key _thumbnail_id and a … Read more