Upgrade SQL Server 2008 R2 to SQL Server 2014 Express - is this supported?

Hi all,

One of our application servers has the following config:
Windows Server 2008 R2 Standard 64 bit
SQL Server 2008 R2 Standard 64 bit (Full licensed version) - build version = 10.50.2500.0

If possible, we wish to perform an in place upgrade of SQL to SQL Server 2014 Express (as Express does not require an SQL license).
Given the server configuration, could any good folk from Microsoft please confirm whether or not this is a supported SQL upgrade path?
I checked the Supported Version and Edition Upgrades link below, but it does not clearly state our current server config so I am still unclear:
https://msdn.microsoft.com/en-gb/library/ms143393.aspx
Any ...