Have never upgraded firmware for my mains DSP5500 upgraded to 24/96k. Is the firmware upgrade worthwhile regarding processing resolution? The others don't seem like a big deal. My center channel is a DSP5000C.

DSP5500 Product Firmware Release 5.40 (2011-10-31)

Software Fixes - Useful - May be useful to upgrade but not essential
Aux legend becomes SLS and VCR3 legend becomes Aux
Aux/SLS source defaults to 4C comms type
Optional support for M80 remote
Improved processing resolution
Better integration with two way speakers in theatre systems
Crossover improvements

DSP5500 Product Firmware Release 5.20 (2007-11-16)

Software Fixes - Useful - May be useful to upgrade but not essential
Improved crossover.

DSP5500 Product Firmware Release 5.10 (2006-08-02)

Software Fixes - Useful - May be useful to upgrade but not essential
Volume control responds according to system address - relevant to some two-room systems.
Latency through DSP speakers unified at 7.5ms.

Trinnov Altitude 16, 271, DSP7200SE front L/R, DSP7200SE HC center, 556 amp for rear surrounds, Magnetar UDP800 universal disc player, REL Acoustics Subwoofer Carbon Special, ROON Nucleus One,
Direct TV satellite box, Xbox One S, Nintendo Switch, Sony XR 77A80J OLED