They're not going to jail. Their 20-month sentence was wholly suspended, so they're free men provided they abide by court rulings and keep their noses clean in the meantime.
The fine, though, is likely to be monstrous. The first instalment is 500,000 Euros, with speculation that the total fine could be up to 10 million Euros.
Regardless, they're planning an appeal, which I'm sure will take a long time.