Has something changed with Zend while I was away

I have been away for a couple of months and haven’t used SC in that time. Nevertheless nothing has changed on my server during that time.

When I went to start SC today I get
“Zend Guard Run-time support missing!
One more more files on this web site were encoded by ZendGuard and the required run-time support is not installed orproperly configured.”

Checking phpinfo() I see
This program makes use of the Zend Scripting Language Engine:
Zend Engine v2.5.0, Copyright © 1998-2013 Zend Technologies

with Zend OPcache v7.0.3-dev, Copyright © 1999-2013, by Zend Technologies

I re-installed Zend, but same thing. Server is Ubuntu 13.10/ PHP 5.5

Can anyone help?

Quick rummage about I see the current Zend is listed for PHP5.4 but Ubuntu server installs PHP 5.5. - is that the problem?