i am using IPS 4240, from cisco website im trying to update the signature. I first downloaded the latest release S505 but this update I could not installed to IPS then I use S479 which was able to update IPS signature. I think I could not install S505 because of the IPS engine which is E3 in our IPS. But when i go through All release tree, I found that latest release fro E3 is S479 and starting release for E4 is S481. so my question is, will i not be able to update my IPS signature after i install this S479 release and If i am not able to update after this release what should i do to update my IPS signature?