Hi nuovaerb
To update Kute theme, you have to download the latest theme package from the http://themeforest.net/download and do as some steps below:
Step 1: Backup your site( Include codes + Database)
Step 2: From the dashboard>>Appearance>>Theme, you need to activate the default template( Ex; Twenty Seventeen theme)
( you can refer this document, it's the same http://test.kutethemes.net/koolshop_doc/#mazanoupdate)
Step 3: Click on Kutetheme and then click Delete( look down in the right). NOTE: DO NOT delete the Kutetheme-Child, currently you have not install it.
Step 4: Return the dashboard choose Plugins then deactive the Kutetheme Toolkit, Slider Revolution, WPBakery Visual Composer and delete them.
Step 5: Return the Appearance menus choose Theme>>Add New>>choose your latest theme version>>Install
Step 6: Return the Plugins menus>>New>>and choose the Kutes Toolkit (Slider Revolution, WPBakery Visual Composer plugins are the same)>>Install>>and activate them.
About color text in the home page, you can go to the dashboard choose Theme Options>>Color and changes as the attachment screenshot
Please do it and let me know.