1. Download zip from this link
2. Use FTP to open /yourwordpressfolder/wp-content/plugins
3. Delete existing wpdatatables folder.
4. Upload previously downloaded wpdatatables folder through FTP to plugins folder (unzip it)
5. Go to WP-admin panel, open Plugins section.
6. Deactivate wpDataTables, and then activate it again.
IMPORTANT: Do NOT delete the old version from WP-admin (by clicking “Delete” in the plugins page) if you don’t want to lose all your tables!