error:0308010C:digital envelope routines::unsupported

Earlier I was using WinSCP 5.6 version that connects using FTP using a p12 keystore, works perfectly , post upgrading to 6.3 version FTPS doesn't work prompts for a certificate passphrase and when entered the passphrase of private key it gives error -

error:0308010C:digital envelope routines::unsupported

What nonsense kind of bug is this ????
Please fix it.

Can you share an example of the certificate file format that you are having a problem with?

Can you find out in what WinSCP version was the problem introduced? You can download past versions of WinSCP from:
https://sourceforge.net/projects/winscp/files/WinSCP/