I'd be suggesting that if the controller is still running ICP 9 then a hardware refresh should be on the cards and not just a software upgrade. Also guessing that if it is currently on ICP release then if you aren't refreshing the hardware then having a spare HDD and a good backup handy would be a must as that HDD probably hasn't done very much work for a while and a power down could be the end of it.
I have to somewhat disagree, although if the customer is open to it I wouldn't discourage it.
Mitel hardware in general has an incredibly long usage life, I have machines that started as ICP 7, maybe older, still happily and efficiently processing calls on MiVB 7.2 and likely will continue to do so on MiVB 8, 9, and 10.
There are literally 30 year old Mitel's out there still chugging along, and many of them will be for another 5 or even 10 years.
That being said, if a customer asks me I tell them the hardware typically has a 7-10 year lifespan for any telephony hardware, regardless of manufacturer.
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