When version 2.40 was released, massive amounts of angry customers started calling in saying the firmware bricked their PS3. Shortly after, Sony yanked the firmware down and replaced it with version 2.41.
You would think Sony learned their lesson that time but, they have just released version 2.42. Once again, people are reporting problems with this version. Anywhere from Blu-ray discs not playing to being unable to get online.
If I was a betting man, I would bet version 2.43 is going to come very soon.