[cisco-voip] clarification of "Obsolete notices"

[paul dial]

I subscribe to Cisco's notification tool to
receive notices about Cisco software.  Recently, I've received
notices that a particular software version is "Obsolete".   
To further confuse matters, the obsolete version of software is  shown as
the latest version available for download from the Cisco website. 

Here is an example taken from one of the notices:

----------------------------------------------
Software Updates-Cisco Unified Communications Manager Version 7.1-08/30/2010 03:34 GMT-08/31/2010 07:34 GMT
.
.
.
Release Version: 7.1(5b)SU2
Release Page Url:
http://tools.cisco.com/support/downloads/go/ImageList.x?relVer=7.1(5b)SU2&mdfid=282421166&sftType=Unified
Communications Manager Updates&treeMdfId=278875240
<http://tools.cisco.com/support/downloads/go/ImageList.x?relVer=7.1%285b%29SU2&mdfid=282421166&sftType=Unified%20Communications%20Manager%20Updates&treeMdfId=278875240>
Release Date: 2010-08-10 22:05:24.0
Description: This software version has become obsolete. ,Obsolete .
---------------------------------------------------

Note that 7.1(5b)SU2 is still the latest version available for download
from Cisco's website.

We can't make decisions based  upon the information provided.  Does the software that we are 
potentially running have a major flaw, or a vulnerability which would  require us to upgrade or change versions?  Immediately?  If the most  recent versions of new code are obsolete, should we delay some of the  upgrades we are testing and planning?

Then there are are EOS/EOL versions of software, which do not seem to
correlate to the Obsoleted versions.  Is there a difference between the two?

Can anyone clarify the meaning of "Obsolete"?  Also, where can we
find information about why the software is obsolete and is there a
recommended version to move to?

Thanks,

paul