Does anyone know why they changed that? Is it still ok to use the old one?

They changed the formula a couple of years ago. You can still use it, but if your food has more than 4 grams fiber, just don't enter more than 4.

Basically, the WW system works. They have made changes through the years but the primary system is the same. I have friends that still use the "old" system and are continuing to lose weight and maintain their goals. I think as long as you are consistant with what you are doing you will be okay.

Yes you can still use it and depending on the program you use (1-2-3, Winning, Flex) you can choose to use the 'unlimited' fiber (but remember that is where many stalled or started to not lose and gain because of the calories that the high fiber items had). Most leaders will say you can still use that slider but just remember if somethign has 10 gms of fiber you can only count 4 gms.