Go to wp-content > themes and backup your UDesign theme folder. After backing it up, simply delete it.
Unzip u-design.zip from the package you downloaded from Themeforest, and get the UDesign theme folder.
Drag and drop the new UDesign theme folder into wp-content > themes field.
Don’t forget to update included plugins.
Navigate to Appearance > Themes on WordPress admin and click again Save Changes button.
Finally, if you have translated the theme, don’t forget to fetch the language folder from backed-up folder and place it in the same directory as an old language folder. If not, you will not have a translated theme.
