Mobile Internet Kit is now part of the operating system. Version 4.0 adds an attention manager to coordinate information from different applications, with several possibilities to get the user's attention, including sound, LED blinking or vibration. 16-bit color screens and different time zones are supported. This version also has security and UI enhancements.

Palm OS 4.1 is a bugfix release. It was introduced with the launch of the Palm i705. The later minor OS update to version 4.1.2 includes