Note: After updating theme or plugin from Envato, please remove server or plugin cache as well as your browser cache in case if you see something is broken or missing and then test your website.
First you needs to update Litho theme with the latest version, see article Update Litho Theme for more information. And then only follow below steps to update theme included plugins.
Step 1: Login to your WordPress Dashboard and Click on Plugins.
Step 2: Select Litho Addons and Slider Revolution plugins by checking the checkbox for each item and select Deactivate option from bulk option dropdown at the top left of the plugin listing grid and click Apply button. This will deactivate the selected plugins.
Step 3: Again select Litho Addons and Slider Revolution plugins by checking the checkbox for each item and select delete option from bulk option dropdown at the top left of the plugin listing grid and click Apply button. This will delete the selected plugins.
Step 4: Now go to Appearance > Theme Setup > Install Plugins and here you can install & activate Litho Addons and Slider Revolution plugins to have their latest versions.