Hello @nzhanaev01,
SSH 3.0 is just a client version, till now the official protocols are SSHv1 and SSHv2. Refer to the below link.
- http://www.vandyke.com/products/vshell/faq/015.html
Also for further information about SSH you can consult into the RFC4253
- https://tools.ietf.org/html/rfc4253