Macromedia Flash Communication Server MX Professional 1.6
Flash Communication Server MX Pro 1.5: 
S/N: SFD150-54410-40240-78359 
S/N: SFD150-52010-23140-64093 
S/N: SFD150-56410-40440-92348 
 
Flash Communication Server Capacity Upgrade: 
S/N: SFD150-56474-24239-95941 
S/N: SFD150-52070-85539-48899 
S/N: SFD150-54278-61539-27333 
 
1) Install v1.5 first. 
2) Stop all services of Flash Communication Server. 
3) Copy v1.6 upgrade files to overwrite installed v1.5 files. 
4) Start its services, then use its "Admin Console" to add both "Professional" keys and "Capacity Upgrade" keys to get unlimited connections/bandwidth(VOLUME license).