No you can definitely upgrade to 1.1.4 if you've downloaded the latest ver of ziphone, download the 1.1.4 firmware file and connect your phone and launch itunes, put your phone in restore mode by holding the sleep/home buttons together for about 20-25 secs,a message will come up in itunes saying it has detected your phone in recovery mode. From there go to the restore button on itunes and hold shift and click the button, a window should open up allowing you to select your downloaded file(wherever you saved it). Simply restore to 1.1.4 and when finished close itunes and any itunes processes which may be running using task manager,then launch ziphone and hit do it all. It's that simple.
For customize to work if you are remaining on 1.1.3 do the following
1)install the old ver of customize(ver 1.21) restart your springboard then uinstall it
2)add the following source in installer
http://www.dlubbat.com/iphone.xml as gavko stated
3)restart springboard and reboot your phone,it should work after that.
4)Not all the features are functional so be aware of that
Hope this helps