Exporting Content wordpress 4.7.3

[ Moderator note: moved to Fixing WordPress. ]

I have a theme and have import demo option it needs to export the content from my demo and compress it to be filename.xml.gz then adding this file to my import folder , if I export the content from wordpress 4.7.3 it make import for all content excepted my menu items but if I Export the content from wordpress 4.5 it make the import for all content and for menu items , please suggest what is the problem in wordpress 4.7.3