Intl 5.0 firmware update brochure
US market 5.0 firmware update brochure
US PDF has the stuff about the wifi adapters removed.
Tho doesn't seem missing from US FDA approval docs circa 2011:
http://www.accessdata.fda.gov/cdrh_docs/pdf/P910023S257M.pdf
"Additionally, a new wireless kit is being provided in version 5.0 for Merlin@home patients to use with their broadband internet connection instead of a landline or cell phone connection. This new wireless kit includes a USB wireless adapter and cable, wireless access point and Ethernet cable attached to the wireless access point as well as a wireless access point power supply."
Certainly only the pay-SJM-every-month cell service is acknowledged about anywhere else though. I dunno.