I had Magento 2.0.7 installation and my site worked fine.
Then recently I updated my site to Magento 2.1.0 and header section on my site is not visible now
What could be the issue.
I had similar issue after upgrading from 2.0.4 to 2.1.0 but then only some of the header content was not showing.
After few hours of debugging I realised that some of the references in out theme xml files was not working because Magento core team changed the name of
header.panel container to
header.panel.wrapper so we needed to modify our theme with the new name
Check default.xml in 2.0.4 and find
<referenceContainer name="header.container"> <container name="header.panel" ... >
And then default.xml in 2.1.0
<referenceContainer name="header.container"> <container name="header.panel.wrapper" ... >
I am not sure in which version this change is added and why but I compared directly 2.0.4 and 2.1.0 and notice it.