PortableApps updater prompted me to update Firefox this morning. It goes through the download process, then the following error appears:
The downloaded copy of Firefox is not valid and can not be installed.
This could be due to an incomplete download or other network issue.
Please try running the updater again when complete.
I have restarted my PC several times since then, and it's the same issue at each restart.
Windows 10 Home. No known network issues; all works normally.
Please assist; thanks!
Problem fixed itself after a few hours and a few restarts.
I'd inadvertently pushed the wrong set of file hashes for 87 of today's 126 Firefox packages released. I've fixed the issue. Apologies for the inconvenience and thanks for the heads up.
Sometimes, the impossible can become possible, if you're awesome!