Copssh version 6.2.2 installers come with LibreSSL 2.7.4  which is a security update with  the following changes:

• Avoid a timing side-channel leak when generating DSA and ECDSA signatures. This is caused by an attempt to do fast modular arithmetic, which introduces branches that leak information regarding secret values. Issue identified and reported by Keegan Ryan of NCC Group.
• Reject excessively large primes in DH key generation. Problem reported by Guido Vranken to OpenSSL (https://github.com/openssl/openssl/pull/6457) and based on his diff.

Copssh version 6.2.1 installers come with LibreSSL 2.7.3 and an updated cygwin1.dll  (2.10.1 - 20180214), which fixes a newly introduced bug causing files with temporary flag on being not visible for operations. See here  for more information.

Copssh version 6.2.0 installers contain OpenSSH 7.7p which is primarily a bugfix release. Major relevant changes:

• ssh(1)/sshd(8): Drop compatibility support for some very old SSH implementations, including ssh.com <=2.* and OpenSSH <= 3.*. These versions were all released in or before 2001 and predate the final SSH RFCs. The support in question isn't necessary for RFC-compliant SSH implementations.
• sshd(8): Add "expiry-time" option for authorized_keys files to allow for expiring keys.
• ssh(1)/scp(1)/sftp(1): Add URI support to ssh, sftp and scp, e.g. ssh://user@host or sftp://user@host/path.  Additional connection parameters described in draft-ietf-secsh-scp-sftp-ssh-uri-04 are not implemented since the ssh fingerprint format in the draft uses the deprecated MD5 hash with no way to specify the any other algorithm.

Copssh version 6.1.3 comes with the latest version of LibreSSL (2.7.2). Cygwin and other GNU tools are also updated to their latest available version.

Copssh version 6.1.2 comes with the latest version of LibreSSL (2.6.4). A predefined working directory (inst_directory\_work) is now used to unpack subinstallers and other installer tools, allowing anti malware/virus programs for exclusion in a deterministic way if necessary. Working directory will be removed upon a successful installation.