I would like to point out that the main site uses some technologies that are not supported under Windows XP: https://support.cloudflare.com/hc/en-us/articles/204846347-Which-browsers-are-supported-for-Universal-SSL-
I am not sure if the problem is well-known.
Are you speaking from experience or just based on what’s written on that page?
I assume that latest version of Chrome and/or FireFox that is available on XP would work, because it’s a browser thing, not OS thing.
If someone uses a browser that doesn’t support cloudflare’s ssl, then they don’t see a lot of internet and I’m not going to bend backwards to support them.
If I hadn’t run across the problem, I would never have traced that page. Any Blink-based browser, including Google Chrome, shows this error message:
A relevant discussion: https://bugs.chromium.org/p/chromium/issues/detail?id=436052
Mozilla Firefox does open the site, but I would rather download Sumatra PDF from a third-party site than use a rustier and clunkier browser, which Firefox is.