keyboard. The original IIe uses a case very similar to the Apple II Plus, painted and with Velcro-type clips to secure the lid with a strip of metal mesh along the edge to eliminate radio frequency interference. The new case is made of dyed plastic mold in a slightly darker beige with a simplified snap-case lid. The other noticeable change is a new keyboard, with more-professional-looking print on darker keycaps (small black lettering, versus large white print). This was the first cosmetic change. Enhanced IIe In March 1985, the company replaced the original machine with a new revision called the Enhanced IIe. It is completely identical to the previous machine except for four chips changed on the motherboard (and a small "Enhanced" or "65C02" sticker placed over the keyboard power indicator). The purpose of the update was to make the Apple IIe more compatible with the Apple IIc (released the previous year) and, to a smaller degree, the Apple II Plus. This change involved a new processor, the CMOS-based 65C02 CPU, a new character ROM for the text modes, and two new ROM firmware chips. The 65C02 added more CPU instructions, the new character ROM added 32 special "MouseText" characters (which allowed the creation of a GUI-like display in text mode, similar to IBM code page 437), and the new ROM firmware fixed problems and speed issues with 80-column text, introduced the ability to use lowercase in Applesoft BASIC and Monitor, and contained some other smaller improvements (and fixes) in the latter two (including the return of the Mini-Assembler—which had vanished with the introduction of the II Plus firmware). Although it affected compatibility with a small number of software titles (particularly those that did not follow Apple programming guidelines and rules, used illegal opcodes that were no longer available in the new CPU, or used the alternate 80-column character set that MouseText now occupied) a fair bit of newer software — mostly productivity applications and utilities — required the Enhanced chipset to run at all. An official upgrade kit, consisting of the four replacement chips and an "Enhanced" sticker badge, was made available for purchase to owners of the original Apple IIe. An alternative at the time, which some users chose as a cost-cutting measure, was to simply purchase their own 65C02 CPU and create (unlicensed and illegal) duplicates of the updated ROMs using re-rewritable EPROM chips. When Apple phased