The new era of sha-256 as opposed to sha-1 signed SSL certificates is slowly gaining the pace, not without a gentle push from the browser providers . And Checkpoint is catching up in its new version R77.30 for Open Servers.
While on both versions – 77.20 and 77.30 cpopenssl package gives the same version info they do differ:

cpopenssl command accepting -sha-256 option

openssl in R77.30 now supports SHA-256 certificates

It doesn’t mean earlier versions do not support SHA256 certificates – just that you cannot issue CSR requests signed with SHA256. Nevertheless, your SSL certificate provider technically is very much able to issue SHA-256 certificate based on SHA-1 signed CSR requests as both are not really related.