Mixing INNPM01's, INNPM11's and INNPM12's for redundancy.
An INNPM01 can operate redundantly with an INNPM11 if the firmware revisions are the same.
An INNPM01/11 can operate redundantly with an INNPM12 If the firmware revision of the NPM01/11 is greater than E.0 and the NPM12 is operating in the CNET mode. Under these conditions, you can operate different firmware's in redundancy together, but, we do not recommend mixing firmware. This means that firmware may be swapped out of the backup module of an on-line node without affecting on-line redundancy communications.
The problem when mixing firmware in a redundant configuration is that you do not get the benefit of the newer firmware if it is the redundant module.
If the newer firmware is the primary module and it fails over to the module with the older firmware, you might see problems with the older firmware that the newer firmware had fixed.