In the new version of WinSCP, I see the binaries of 5.1.6. I think it doesn't update the winscp.exe with the correct version.
New: Ferdium (May 16, 2024), Platform 29.5.1 (May 08, 2024)
1,100+ portable packages, 1.1 billion downloads
Please donate today
I've confirmed this issue, and sent a fix for release.
Thanks! I am waiting that fix to add the new one into my PortableApps repository