In F-12, Evolution was configured to display X-CRM114-Status and X-Spam-Report headers. On upgrading to F-13 these headers are no longer being shown.

[dwmw2@macbook ~]$ gconftool-2 --get /apps/evolution/mail/display/headers
[<?xml version="1.0"?>
<header name="From" enabled=""/>
,<?xml version="1.0"?>
<header name="Reply-To" enabled=""/>
,<?xml version="1.0"?>
<header name="To" enabled=""/>
,<?xml version="1.0"?>
<header name="Cc" enabled=""/>
,<?xml version="1.0"?>
<header name="Bcc" enabled=""/>
,<?xml version="1.0"?>
<header name="Subject" enabled=""/>
,<?xml version="1.0"?>
<header name="Date" enabled=""/>
,<?xml version="1.0"?>
<header name="Newsgroups" enabled=""/>
,<?xml version="1.0"?>
<header name="Face" enabled=""/>
,<?xml version="1.0"?>
<header name="x-evolution-mailer"/>
,<?xml version="1.0"?>
<header name="Resent-Date" enabled=""/>
,<?xml version="1.0"?>
<header name="Resent-From" enabled=""/>
,<?xml version="1.0"?>
<header name="Resent-To" enabled=""/>
,<?xml version="1.0"?>
<header name="Resent-Cc" enabled=""/>
,<?xml version="1.0"?>
<header name="X-Spam-Report" enabled=""/>
,<?xml version="1.0"?>
<header name="Organization" enabled=""/>
,<?xml version="1.0"?>
<header name="X-Crm114-Status" enabled=""/>
]