Note that any installed Alpha version will have to be removed before installing the Beta.
You'll have to manually add the below hook call to ExpressionEngine:
system/ee/legacy/core/Output.php:276 within the _display() method.
if (ee()->extensions->active_hook('before_response_send_output') === true) {
$output = ee()->extensions->call('before_response_send_output', $output);
if (ee()->extensions->end_script === true) {
return;
}
}
During the Alpha phase, the previous version should be completely uninstalled through ExpressionEngine and, ideally, the files removed, before installing the latest version.
Once the Beta starts, Updating should follow ExpressionEngine norms.