https://filezilla-project.org/ has restartable download after fail
I have an Internet service which Speed tests to 0.58 mbps. It is slow, yes. PrortableApps downloads will fail on my computer. Its download code can't restart from a failure point. Thus there are problems of installing Apps and updating Apps.
I just happen to know of an open source file transfer client utility and a matching server side damon, the https://filezilla-project.org/ that tries to restart download failures. I don't know if its restart code could be made available to help make slow systems like I have and flaky networks downloads be more reliable.
Since it's open source and if the license is open, maybe FileZilla's restart code could be a guide for development of algorithms that could restart PortableApps during slow downloads or when there are network connection problems.
Well it's just a thought.
johnswolter
The PA.c Platform's Updater/App Store uses the Windows internet components. They can handle slow connections. They can't resume from a failure point with the current NSIS (the language the updater/app store are written in) components.
I'll be switching them to a more robust download component using the nsCurl plugin shortly. It's already working in internal testing. It supports resume after disconnections.
Sometimes, the impossible can become possible, if you're awesome!