Over the last 6 years I have worked as a VSA (Volunteer Services Abroad) volunteer from New Zealand in developing countries, helping with setting up small networks and tutoring people on the use of software.
I have recently installed Ubuntu & LibreOffice in Tonga for the ministry of tourism and New Ireland (PNG) for the Community Development division of the Provincial Administration.
In both cases I have installed small LANs with a Ubuntu Server (12.04) and approximately 70 desktop & laptop PC running Ubuntu 11.10.
I have been able to do this as I could "purchase" the systems on DVD and install the OS on all machines from DVDS.
The reason to use DVDs is the lack of internet connections. Oh we do have one, but to download Ubuntu 13.04 will take approximately 4 DAYS!. That is if the ISP stays operational for that time and if the PNG power company manage to generate power for longer that a few hours.
The situation was or is the same in Tonga.
Now I am a great advocate of Open source software, especially in developing countries that do not have access to computer shops or internet.
The Community Development had 4 desktop PCs and several laptops, with a variety of unlicensed Microsoft OSs (XP, Vista, Windows 7). They were running variations of Microsoft Office (2003, 2007 & 2010). There was not a central server.
My task was to install a server and LAN, plus design a database for the division to maintain a complex pension scheme.

How am I to "update" the systems?

Bring back the DVDs

Don't forget more than half the worlds population does NOT have internet access!

Tony Bray