You'll probably need to update at least the CTI Manager from the Witness.
I suggest you to upgrade to an Active Call Recording Solution. It's more reliable and less bandwidth consuming. Witness seems to got one. The wisest thing to do is to build a sandbox and run your tests in there.
I use ASC evoIP Active and it's working perfectly in 6.1.2.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.