If you have customized the theme folder and want to prevent WordPress from updating it then simply edit theme/style.css and update the version number to a very high number.
Disable Astra theme update
Open wp-content/themes/astra/style.css
Theme Name: Astra
Theme URI: https://wpastra.com/
Author: Brainstorm Force
Author URI: https://wpastra.com/about/
Description: Astra is fast, fully customizable & beautiful theme suitable for blog, personal portfolio, business website and WooCommerce storefront. It is very lightweight (less than 50KB on frontend) and offers unparalleled speed. Built with SEO in mind, Astra comes with Schema.org code integrated so search engines will love your site. It offers special features and templates so it works perfectly with all page builders like Elementor, Beaver Builder, Visual Composer, SiteOrigin, Divi, etc. Some of the other features: # WooCommerce Ready # Responsive # RTL & Translation Ready # Extendible with premium addons # Regularly updated # Designed, Developed, Maintained & Supported by Brainstorm Force. Looking for a perfect base theme? Look no further. Astra is fast, fully customizable and WooCommerce ready theme that you can use for building any kind of website!
Version: 1.4.8Change to:
Theme Name: Astra
Theme URI: https://wpastra.com/
Author: Brainstorm Force
Author URI: https://wpastra.com/about/
Description: Astra is fast, fully customizable & beautiful theme suitable for blog, personal portfolio, business website and WooCommerce storefront. It is very lightweight (less than 50KB on frontend) and offers unparalleled speed. Built with SEO in mind, Astra comes with Schema.org code integrated so search engines will love your site. It offers special features and templates so it works perfectly with all page builders like Elementor, Beaver Builder, Visual Composer, SiteOrigin, Divi, etc. Some of the other features: # WooCommerce Ready # Responsive # RTL & Translation Ready # Extendible with premium addons # Regularly updated # Designed, Developed, Maintained & Supported by Brainstorm Force. Looking for a perfect base theme? Look no further. Astra is fast, fully customizable and WooCommerce ready theme that you can use for building any kind of website!
Version: 9.9.9
Then no theme update will be advertised.