The update should be offered in the Plugins section if you activated the purchase code in wpDataTables Settings/Activation. On some WordPress installations, you need to deactivate the plugin first to see the update offered, so please try that.
If that doesn't work, try going through Dashboard/Updates. See if you can update the plugin through there, and if that doesn't work either, you can follow the manual update procedures below.
First, log into our store with the credentials you received when you purchased wpDataTables, and download the installation file from there, or from Envato (depending on where you purchased the plugin from).
MANUAL METHOD 1:
Go to wpDataTables Settings/Main Settings, and make sure that the "Prevent deleting tables in database" checkbox is ticked.
Access the Plugins section and deactivate the plugin.
Click on Add New, and upload the file you previously downloaded.
When you upload the file, WordPress will inform you that you're replacing the plugin with the new version, so confirm that. After the plugin is installed, activate it, and make sure to purge all cache from your website.
MANUAL METHOD 2:
Use FTP to open /yourwordpressfolder/wp-content/plugins
Delete the existing plugin folder ("wpdatatables")
Open the zipped file, and extract the "wpdatatables" folder you see in the zip file into ../wp-content/plugins/ folder
Go to the WP-admin panel and open the Plugins section
Deactivate the plugin, and then activate it again
Clear server and browser cache
MANUAL METHOD 3:
Go to wpDataTables Settings/Main Settings, and make sure that the "Prevent deleting tables in database" checkbox is ticked.
Go to the Plugins section, deactivate the plugin, and then delete it (you will not lose your data because you made sure the database tables are not deleted).
Click on "Add New" in the Plugins section, and upload the previously downloaded file.
Activate it and make sure to purge the server and browser cache.