How to save in docx (Office 2010) format, vs doc (2003) fmt?

My compile options only include .doc (Windows Office 2003) format, not docx. However, I think I used to see docx as an option. Was this taken out in a recent update? If not, how do I get it back?

The .docx format is only available by using Word’s converters, so you need to have a copy of Word 2007 or higher installed and then enable “Use Microsot Word or Open Office for doc and docx conversions” in the Import/Export tab of Tools > Options in Scrivener. After enabling the option, reload the project to have the .docx format appear in the compile format options.