lelandf

By default, WordPress will not apply <a href="https://codex.wordpress.org/Configuring_Automatic_Background_Updates" rel="nofollow ugc">automatic background updates</a> if it detects a version control system (like Git or Subversion) in the WordPress directory or any of its parent directories.
WordPress does this because it assumes that if version control systems are present, the site owners have their own system in place for managing updates, and WordPress doesn’t want to mess with that.
However, minor updates can contain critical security vulnerability fixes, and those aforementioned site owners may consider the benefit of having minor releases automatically updated by WordPress greater than the risks of waiting too long to apply those updates themselves.
If that sounds like you, then you may wish to consider installing this option-free plugin.
Just activate when you need it.
Perhaps before a “disconnected” vacation when you don’t want to run the risk of a security update being released during it, and having no way of applying said update until your return.
Deactivate it when you don’t.

Forced Auto Updates

Apply automatic background updates for minor releases of WordPress core, even with version control systems present.

gr8nilay

This plugin is use to disable all your theme updates as well as notifications for the same. It will prevent your wordpress to check for new updates for each theme. This plugin is ideal for whom who have customzied the theme and won’t loose their customization at time of update.
Read This First: 
You need to keep your WordPress updated with themes and plugins so if you fail for the same then it will might compromise security of your site.

Disable WP Theme Updates Advance

Easy to install and automatically disable all theme updates.



Nice..!!

Disable all your WordPress theme updates on plugin activation.

Forced Auto Updates vs Disable WP Theme Updates Advance