Please note this is an old forum thread. Information in this post may be out-to-date and/or erroneous.
Every phpdocx version includes new features and improvements. Previously unsupported features may have been added to newer releases, or past issues may have been corrected.
Yes, as you explain, first you need to replace the placeholders in the external file and then add it to the new DOCX. Or you can use merging features to merge DOCX documents and replace placeholders any time.