How do I update a custom theme

Here is a full documentation for how to do this:
Github updater – Documentation

Upload in wordpress

Download the latest tagged archive (choose the “zip” option).

Unzip the archive, rename the folder correctly to github-updater, then re-zip the file.

Go to the Plugins -> Add New screen and click the Upload tab.

Upload the zipped archive directly.

Go to the Plugins screen and click Activate.

[Description]

This plugin was designed to simply update any GitHub hosted WordPress
plugin or theme. Your plugin or theme must contain a header in the
style.css header or in the plugin’s header denoting the location on
GitHub. The format is as follows.

GitHub Plugin URI: afragen/github-updater

GitHub Plugin URI: https://github.com/afragen/github-updater

or

GitHub Theme URI: afragen/test-child

GitHub Theme URI: https://github.com/afragen/test-child

…where the above URI leads to the owner/repository of your theme or
plugin. The URI may be in the format https://github.com/<owner>/<repo>
or the short format <owner>/<repo>. You do not need both. Only one
Plugin or Theme URI is required. You must not include any extensions
like .git.

[Usage]

Plugins

There must be a GitHub Plugin URI, Bitbucket Plugin URI, or GitLab Plugin URI declaration in the plugin’s header.

/*
Plugin Name:       GitHub Updater
Plugin URI:        https://github.com/afragen/github-updater
Description:       A plugin to automatically update GitHub, Bitbucket or GitLab hosted plugins and themes. It also allows for remote installation of plugins or themes into WordPress.
Version:           1.0.0
Author:            Andy Fragen
License:           GNU General Public License v2
License URI:       http://www.gnu.org/licenses/gpl-2.0.html
Domain Path:       /languages
Text Domain:       github-updater
GitHub Plugin URI: https://github.com/afragen/github-updater
GitHub Branch:     master
*/

Themes

There must be a GitHub Theme URI, Bitbucket Theme URI, or GitLab Theme URI declaration in the style.css file. When initially adding a theme, the directory must be identical to the repo name.

/*
Theme Name:       Test
Theme URI:        http://thefragens.net/
Version:          0.1.0
Description:      Child theme of TwentyTwelve.
Author:           Andy Fragen
Template:         twentytwelve
Template Version: 1.0.0
GitHub Theme URI: https://github.com/afragen/test-child
GitHub Branch:    master
*/

Hope this helps.

Please let me know

Leave a Comment