SFTP with key file error

Team, I am facing issue in connecting to SFTP using key file. getting error “object reference not set to instance of an object”… exact same issue explained here OpenFtpSession ACTIVITY using Key file and SFTP

Do you have any idea about it? if yes, what is the package version and latest command to be used… I am trying to upload the file

@theerthaks, What version of studio are you using ?

Per this link, Starting with v2018.2, this activity is deprecated.

I use 2019.4.2 version -FYI.
EDIT: I do not have that activity since my version is not supported so can’t try to simulate the issue.

I understand, version is fine… I want to upload file to SFTP using key file… how can we achive that?