how to update KNIME platform or KNIME extensions online behind a firewall, with KNIME 5.3?

Hi, I was using the method to modify urls in the preferences → Install/Update → Available Software Sites from “https://xxx” to “http://xx” to allow online installs/updates behind my organization’s firewall. This works well with KNIME 5.2 and previous version.

However after I updated to 5.3, this method doesn’t work. Below are the error messages I got, don’t know why it still connected to the https site while I’ve already modified all urls to http://

local update from zip file is not quite friendly… any suggestion for this? thanks

Xiaoan