I have several 7970's that are running load file SCCP70-8-2-2SR4S and are not able to call into the unity (voicemail) box. It will connect but never gets a message. I have one 7970 that has load file SCCP70-8-2-1S that can dial into VM successfully. Has anyone seen this? My questions are should I try going to a newer version? Go back (and how do I do this?)? And why does the one 7970 not update like the others have?