How to perform a Manual Update
You can manually update both the Joomla! CMS and 3rd party extensions.
It is preferable to use the Updater Plugins covered elsewhere in this article.
But if this is not possible then you can perform a MANUAL UPDATE via your website control panel.
The Joomla! CMS
You will need to download a package file from the Joomla! Project website:
3rd party extensions
You will need to download a package file from the 3rd party extension developer's website.
Use the link published in the Joomla! Exension Directory.
If you can, avoid using search engines to look for updates. Reason: hackers target users looking for updates!
Download a ZIP file of the extension update (scanning for malware and viruses).
Joomla! Extensions Directory
Make this your one stop shop when looking for 3rd party extension updates.
Do you need to uninstall an extension before installing an update?
As a rule of thumb this should not be necessary, unless the developer categorically states that you should uninstall the existing version of the extension before installing the new one.
Not all developers provide clear instructions.
Another reason to perform a FULL backup of your Joomla! CMS before updating an extension.