Chrome only with Draft 28
What this means?
When TLS 1.3 is being designed, each iteration is called a "Draft". As the design process nears the end the changes between each draft are smaller.
This means that it makes sense to only support the later drafts and then the final version.
Avast now supports TLS 1.3 Draft 26, 27 and 28 and will support the future and final version of TLS 1.3
Chrome uses Draft 23 by default right now. However you can enable usage of Draft 28 manually in Chrome settings.