Hi , I just found the below statements from the documentation "As mentioned before Drools 4.0 is a major update over the previous Drools 3.0.x series. Unfortunatelly, in order to achieve the goals set for this release, some backward compatibility issues were introduced, as discussed in the maiil list and blogs. " Where can i get more information on the backward compatibility issues ? Thanks , Kingston kingston wrote: -- View this message in context: http://www.nabble.com/Does-Drools-4.0-rules-have-downward-compatibility-w... Sent from the drools - user mailing list archive at Nabble.com.