Thanks for your post.
I have added this to the documentation:
https://winscp.net/eng/docs/rawsettings

After I have experimented a lot, I have it figured out:

sessionOptions.AddRawSettings("Compression", "0");
sessionOptions.AddRawSettings("SshProt", "1");

Nevertheless thanks.:mrgreen:

Hello,

I need to upload some files to a server that only understands Sftp SSH-1.
Before asking the question, an update to SSH-2 is not possible.:cry:

I can connect to the server successfully with the desktop tool of WinSCP if I
choose the preferred SSH version 1, but how I do it via .Net.:?:

When running the code below I get the exception "Incoming packet was garbled on decryption"

Thanks in advance.

Source code:

SessionOptions sessionOptions = new SessionOptions
{
Protocol = Protocol.Sftp,
HostName = "192.168.1.230",
PortNumber = 22,
UserName = "root",
Password = "xxxxxxxxxxx",
SshHostKeyFingerprint = null,
};

using (WinSCP.Session session = new WinSCP.Session())
{
// Connect
session.DefaultConfiguration = false;
session.Open(sessionOptions);

.......