Since the safezone browser is based on chromium, it is a custom build with many restrictions on the standard builds. It is also running inside the safezone and not outside it, so less of an issue for normal browsing. Avast do periodically update it.
Thank you, I just think it will be better if avast update it more frequently because security holes could be also at the heart of the browser, in things that were not restricted (version 17 was released a year ago, or maybe they update the browser but not updating the version number that shown)