Hello,
The occurrence option of cloneBlock is available since phpdocx 8.2 . phpdocx 7 doesn't include it, and using this version the block placeholders must be unique; phpdocx 8.2 removes this limitation.
You can upgrade your license on MY PHPDOCX page after login. On https://www.phpdocx.com/news/ you can read the features included in each new version.
Regards.