Based on what I'm reading on the Siemens forums regarding the update for 1851, I would strongly recommend investigating what all is required and what has been problematic before going full production with 1847 and having a solid plan in place for how your facility will handle the update process. Customer default settings can affect the way the update to 1851 is handled, as well as each user's method of connecting to your network and the internet (issues with those using VPNs for example).
Tim Flater
NX Designer
NX 11.0.2.7 MP11 Rev. A
GM GPDL 11-A.3.5.1
Win7 Enterprise x64 SP1
Intel Core i7 2.5GHz 16GB RAM
4GB NVIDIA Quadro K3100M