First of all backup your database follwing these insctructions.
- Get the latest WordPress zip (or tar.gz) file.
- Unpack the zip file that you downloaded.
- Deactivate plugins.
- Delete the old
wp-admindirectories on your web host (through your FTPor shell access).
- Using FTP or your shell access, upload the new
wp-admindirectories to your web host, in place of the previously deleted directories.
- Upload the individual files from the new
wp-contentfolder to your existing
wp-contentfolder, overwriting existing files. Do NOT delete your existing
wp-contentfolder. Do NOT delete any files or folders in your existing
wp-contentdirectory (except for the one being overwritten by new files).
- Upload all new loose files from the root directory of the new version to your existing WordPress root directory.
NOTE – you should replace all the old WordPress files with the new ones in the
wp-admin directories and sub-directories, and in the root directory (such as
wp-login.php and so on). Don’t worry – your
wp-config.php will be safe.
Be careful when you come to copying the
wp-content directory. You should make sure that you only copy the files from inside this directory, rather than replacing your entire
wp-content directory. This is where your themes and plugins live, so you will want to keep them. If you have customized the default or classic themes without renaming them, make sure not to overwrite those files, otherwise you will lose your changes. (Though you might want to compare them for new features or fixes..)
Lastly you should take a look at the
wp-config-sample.php file, to see if any new settings have been introduced that you might want to add to your own
More details here.