What's the advantage over manually updating?

Your technique is very similar to what I personally use when I need to update plugins that can’t be automatically updated, so it works perfectly well. It is also similar to what this plugin does behind the scenes.

This plugin was created due to the following two realities:

• WordPress does not support upgrading a plugin or theme by uploading an updated zip file. When doing this, WordPress says that the plugin or theme already exists and refuses to install the upgrade.
• Most WordPress users are more comfortable using an interface in the WordPress dashboard than they are with unzipping files and using FTP or some similar file utility in order to upload the the plugin or theme files.

At iThemes, we tell people to use this plugin since users have far fewer issues using it than using the manual upgrade guide we used to send people to by default. I’m sure that other authors recommend that people use this plugin for the same reason.

tl;dr: It’s easier to point people to this plugin than it is to educate every user about how unzipping works, how theme and plugin directories work, how FTP or their specific host’s file management software works, where plugins and themes live, and how to handle edge cases when things go wrong.

Thanks! That’s really a great reply and I fully understand the ease-of-use part. And as far as I see, it really shines when it comes to plugin updates. I nearly never have the need for updates by uploading a new version, but as far as I remember, just renaming a plugin dir to *.old doesn’t always do the trick. I may misremember, though ??

Again, thanks for your quick reply.

Best regards
Floutsch

Internally, WordPress tracks the active theme and active plugins by path, such as akismet/akismet.php for a plugin or xmpl-theme for a theme. You can test this by renaming an active plugin’s directory and loading up the Plugins page in your dashboard. You’ll see a message stating the plugin was deactivated since it could not be found (I should note that this forced deactivation only happens when that page is loaded when the directory no longer exists; you can remove the directory, play around with the site, put the directory back, and it will remain active). Similarly, if you rename the active theme directory, the site will revert automatically to the default theme.

Since I work on the command line, my typical upgrade technique for both themes and plugins is as follows:

$ cd wp-content/plugins
$ mkdir temp
$ cd temp
$ wget https://example.com/example.zip
$ unzip example.zip
$ mv ../example example.old && mv example ..

I like to chain together the last two commands with && so that if the first one fails, the second doesn’t run. It also ensures that the there is a minimal amount of time where the plugin or theme doesn’t exist.