In 1987 Jeep (transitioning from American Motors control to Chrysler) discontinued the venerable CJ-7 and in its place came the Wrangler.
Aside from square headlights, what changed?
Well, the designation for one thing. 
CJs had been built since 1945: CJ-2, CJ-2A, CJ-3, CJ-3A, CJ-3B, CJ-5, CJ-6 (a stretched CJ5), CJ-7, and CJ-8 (also known as the Scrambler, it was a silmilar concept to the CJ-6), and the mainly-export CJ-10. ‘CJ’ meant ‘Civilian Jeep’, which, while extremely similar to the military models (e.g. MB/GPW – the latter built by Ford, M38, et al.) were designed for the civilian market. They were marketed as ‘do-all’ vehicles that could be used on the farm (PTOs – Power Take-Offs – were useful for running farm machinery) and also be driven into town on a weekend. Similar to the CJs were the DJs, or ‘Dispatch Jeeps’ such as the DJ3A and DJ5 series. These were used by the Postal Service, though others used them as well. The DJ3A Surrey Gala model featured pastel colours (usually pink) and striped tops. DJs were two-wheel drive. Incidentally, the Cherokee is the XJ. The earlier Cherokee was the SJ, and the Grand Cherokee went by ZJ and WJ. The Liberty is the KJ.
The CJ7 was introduced in 1976 and was produced for 11 years. Even Jeeps have to change with the times, and the CJ7 eventually was replaced by the YJ Wrangler. The YJ had a wider stance than the CJ, slightly lower ground clearance, and anti-sway bars; all of which made it more comfortable to drive (by the end of CJ production it seems to me – i.e., I have no cite – that most people bought CJs as cheap convertibles rather than serious offroad vehicles) and reduced the risk of rollover. (You may remember the Suzuki Samurai issue where people did not understand that they were meant to be driven as offroad vehicles and not road cars, and ended up rolling them over when they attempted to turn too fast for the design.) The YJ also featured rectangular headlights. Many Jeep lovers saw this nod to current styling cues as slap in the face to the spirit of the Jeep. Note that the TJ Wrangler rreturned to the traditional round headlights. Speaking of tradition, notice that all CJs, YJs/TJs, and even the XJ have seven-slotted grilles.
Johnny L.A., the originator (though I’ve since given it up) of The CJ2A Page