How to update ssl ?

I using CCR1009-8G-1S-1S+ version 6.34.2 (stable)
With a valid certificates from comodo

COMODO RSA Domain Validation Secure Server CA

When I open https://mydomain.com, chrome warning

Your connection to mydomain.com is encrypted using an obsolete cipher suite.

Can someone help me ?

I think only MIkroTIk can help you by releasing a new version with updated SSL libraries.
But until then, I would not worry too much about it. Those “issues” are mostly theoretical and
will probably not affect you.