OLPC is offering upgrade and repair kits which can take one of the original underpowered XO-1 laptops and turn it into an XO-1.5 or XO-1.75 laptop. (If and when the XO-4 gets into production the earlier models will be able to be upgraded to that model as well.)
There's a number of different kits available, and this is due to the subtle differences between the XO models. For example, upgrading an XO-1 laptop to a later model requires a new motherboard, of course, but it also requires the insertion of a small metal bracket to hold the Wifi card. Early adopters can also order the newer style of keyboards like that found on the XO-1.5 HS.
The XO-4 motherboard will also be available as an upgrade part, and its kit will include a small rubber insert which will assist in modifying one of the 3 USB ports. The XO-4 has only 2 USB ports; the third one was swapped for an HDMI port. Note, though, that XO-4 Touch won't be an upgrade option. Apparently there are some compatibility issues with the IR touchscreen and older XO models.
Even so, this is still a significant piece of news. What other laptop maker offers parts for 5 year old devices, much less an upgrade path which gives you a top of the line device?
And I think it's well worth the expense. The original XO-1 runs on an Intel x86 CPU, while the later models (starting with the XO-1.75) are running on a Marvell Armada CPU. The later models are much more energy efficient as well as faster and more powerful. It makes sense to upgrade as soon as funds as available.
images by One Laptop per Child