If you are a theme author or other 3rd party plugin author, here are some articles about how you can extend GTM4WP and what you need to do in order to keep your theme compatible with GTM4WP.
Download the latest version of my Google Tag Manager plugin for WordPress and start using advanced GTM on your website without coding!Download
Interested in early releases of new features?
Do you want to contribute to the source code?
Visit the GitHub repo of the pluginGitHub repo