You can manually delete and install Jupiter X through the WordPress dashboard. Your settings and content will be safe since it is all stored in the theme’s database.
Deleting the outdated theme version
1. From WordPress left menu, go to Appearance > Themes.
2. Activate one of the WordPress default themes temporarily.
3. Click on Jupiter Theme Details button.
4. In the bottom right corner, click on the Delete button.
Installing the updated theme version
1. Download the theme again from ThemeForest.
2. Extract the downloaded .zip file into a folder.
3. From WordPress left menu, go to Appearance > Themes.
4. Click on Add New Theme button.
5. Click on Upload Theme button.
6. Click on Browse and select jupiterx.zip, then click the Install Now button.
7. Wait for the installation to complete.
8. If the theme is installed successfully, click on the Activate button.
Note: After updating the theme, it is highly recommended to update the bundled plugins. To learn how, check out this article.