Are you have any issues in particular? Or are you just inquiring to help decide whether to upgrade or not? Because as far as I know and can tell(I have been using the IDE with 4.x) it is up to date and working as expected.
Make sure your project .jar file is being compiled to the correct /lib folder. Since you started the project using a previous version of Wowza that was in another location, the IDE is still compiling to the old /lib folder. The easiest way to re-set is to delete the build.xml, then delete the project leaving the check box to "delete files" unselected, then re-create the project with the same name.