your best bet is to start with E-Lab Navigator. It will show you the latest EMC supported version for each switch but also what versions are compatible with each other.  Home > Support > Interoperability and Product Lifecycle Information > E-Lab Interoperability Navigator
Hi,  We have the set of brocade and cisco switches in our DCs.     I've taken up the job for upgrading these switches to the latest firmware supported versions. Any information on this is highly appreciated and let me know the best recommendations while doing this job.  Also I want to confirm if FW upgrades can be done online non-disruptively? and Any support or compatibilty with other devices like HBA, Storage etc needs to be followed or upgraded as well.  Advance Thanks, BMK
Brocade,Cisco Firmware versions