upgrading server to SFTPv4 protocol?

hello,

first thanks for the wonderful software.

a question, when i connect to my server WinSCP reports that i am using "SFTP protocol version 3" which is quite alot slower compared to when using SCP.

i read on the protocols page on this website that SFTP v4 offers major performance improvments in transfer speeds.

how can i upgrade/force my server to use SFTP v4 instead of v3? i am guessing its some setting related to OpenSSH, but i cant figure it out.

I believe that OpenSSH has only v3 server.

I do not know of any performance benefit between v3 and v4. Where did you read it?

i was refering to this paragraph:

"Transfers are slower in general due to necessity to wait for packet confirmations. Since 3.4 several read/write requestes are issued in parallel, what suppresses the disadvantage significantly"

on https://winscp.net/eng/docs/protocols

however upon reading it again, it appears i read it wrong the first time and confused "since 3.4" to be "since 4"

sorry about that :)