Zend Optimizer for PHP 5.5.9 is not compatible

[casperb71]

On my old server (with paralleles12) there was PHP version 5.3.2 installed.
On that server I used an E-mail marekting program named 12All. There for I had to install Zend optimizer and the program works OK.

Now I chanced to another newer server (Ubuntu 14.04 64 bits with PHP 5.5.9 and Parallels 12)
Zend optimizer is not compatible with these PHP version, so I could not install 12All.

Zend company advised me to install Zend Guard but I don't see if this is the right program for it.

Could anyone advice me?
Please keep it simple because my English is not so good (I'm Dutch)

With regards