RIM has struck back at Visto in its latest legal battle.
The company, which settled a patent suit with NTP for $612.5m (about £330m) in March, has countersued in the challenge it faces from Visto.
RIM has asked for three of Visto's patents to be invalidated, and said that it will "consider asserting its own patents against Visto", moves very reminiscent of the early stages of its long-running struggle against NTP.
Visto sued RIM after a court found that a third mobile email player, Seven Networks, had infringed its patent, and ordered Seven to pay $3.6m (£1.9m) damages. Seven is the number-two player in mobile email, with around a million users, compared to RIM's five million.
Visto shouldn't count its chickens, though, as Seven hopes to reverse the earlier judgement. "We don't expect to pay any money," said Paul Hedman, managing director EMEA of Seven. "We will be shipping a workaround in the next version which will not use the disputed technology."
This story first appeared on Techworld.com.