The next release of Net Connect, which will be version 3.2.2, and is due out on October 8, will either have Explorer 5.1 or 5.2.
With current versions of Net Connect it is not possible to use any other Explorer version other than the one it came with. However with this forthcoming 3.2.2 release, you will be able to use any Explorer as Net Connect will not have a dependancy anymore.
So even if NC 3.2.2 only comes with Explorer 5.1, you will be able to upgrade to 5.2 without breaking Net Connect.
There's not really that much else other than some bugfixes. There is an important bugfix included for the DMM (Data Manager Module), for those that use the DMM feature. There's also some srsproxy process bugfixes.
There will be no new features with 3.2.2.