I understand this is not open source, but I could not find any info, at least which version of zend or ioncube is required for me to run cubecart?

please advice.

I don't believe it required either. Are you having problems upgrading?

Actuallu, I did not yet try to install, just reading the site, I see this is not open source, so how could it be encoded without Zend or ionCube?

It's not encoded. The software is free to use, but purchasing a license will remove the CubeCart copyright header and footer and give you additional support from Devellion for a period of time.

Thanks for the advice, I would go ahead for installation!