Apple plans to refresh its 13- and 15-inch MacBook Air laptops with the M4 processor as early as this coming week.The MacBook Airs are usually among the first devices to receive new M-series processors from Apple.Accumulating evidence suggests that the M4 MacBook Air has been in testing and may be ready for a public launch.The new MacBook Airs are expected to have a similar design to the current M2 and M3 models but with improved performance.