Weak algorithm (AES256-cbc) for encryption. Please can remove this private key or change the algorit

Hi Team,
I'm currently using WinSCP to transfer my project files to my client and I have been intimated by my client with the following statement in my email.

your team is using weak algorithm (AES256-cbc) for encryption. Please can remove this private key or change the algorithm or any other method?

Can any one one help me on this
Regards,
Ram Praneeth Yandapalli

How does your client even know, what algorithm are you using for your private key? Is this really about private key or about SSH connection encryption algorithm?

Yeah, it may be with SSH connection encryption algorithm?

If this is about SSH encryption algorithm and your client do not want their partners to use a particular cipher, why don't they disable it on their server in the first place?