Though iOS 4.2.6 was first available as a direct download for review units in January, Apple issued official release notes Thursday to coincide with the launch of the CDMA iPhone 4. iOS version 4.2.6 "fixes a bug to ensure Personal Hotspot data usage is accurately reported (for Verizon iPhones)," according to the notes.
The Personal Hotspot WiFi tethering plan, which supports up to five WiFi devices, costs an additional $20 a month for 2GB of tethered data. Each additional gigabyte used will cost $20.
The promptly released fix could be an effort by Apple and Verizon to head off a public relations nightmare from any billing errors as a result of the bug. Verizon has previously come under fire for its billing practices. In 2009, the FCC initiated an investigation of a hard-wired "Wireless Mobile Web" button that would charge Verizon users $1.99 when pressed.
Last October, Verizon began refunding to customers up to $90 million in erroneous "data usage" charges.
However, Verizon is not alone in receiving accusations of overcharging practices. Apple's long-time partner AT&T was recently the target of a class-action lawsuit alleging that the carrier measured data "like a rigged gas pump," routinely overcharging customers.