Hello,
After upgrading your license to phpdocx 14, you just need to download and include the new package. All methods and options of phpdocx 11 are compatible with phpdocx 14.
New versions of phpdocx add new methods and options. We keep the compatibility with the API since phpdocx 4. On https://www.phpdocx.com/news/ you can read all new features included in each new release. Of course, we recommend you test the new version before copying it to production.
If you have any question or doubt after upgrading to phpdocx 14 do not hesitate to contact us on this forum or contact[at]phpdocx.com.
Regards.