Manually Upgrading Wordpress
Always backup content before beginning the manual update in case a revert is needed.
When updating WordPress before your plugin authors have tested their plugins with the latest version of WordPress then you could run into trouble. Its recommend that you deactivate all plugins before upgrading WordPress then activating them after the upgrade has concluded. Please be aware of what you are using the plugin for and if its is necessary to keep, or can be replaced by a new existing method we use today.
/wp-includes and /wp-admin directories on your server. (Using FTP, File Manager or Shell SSH)/wp-includes and /wp-admin folders (directories) to your server. (Using FTP, File Manager or Shell SSH)/wp-content folder and upload the individual files from the new folder to existing /wp-content folder (Using FTP, File Manager or Shell SSH), overwriting existing files./wp-content folder./wp-content directory (except for the one being overwritten by new files).xml-rpc.php and all wp-\*\*\* files in the root folder except wp-config.php. Upload all remaining new individual files from the root directory (folder) of the new version to your existing WordPress root directory.Update WordPress by logging in to your dashboard and follow the update instructions.
Update existing WordPress Plugins to latest version that are compatible with the newest WordPress Version or if time allocates replace with new methods we use today.