In datasheet on cisco.com I see that SPA9000 initially supports 4 SIP-compatible IP phones and is upgradable to 16 IP phones with an easy-to-install license key upgrade. Partnumber for license upgrade is SPA9000UPG. But I don't see this position in price list.
Is this license still actual?
or may be it is not required now
This change was done in firmware 5.2.5. I'm attaching the release notes for your reference.
indeed, the license is not needed any longer. Please upgrade the SPA9000 to the latest/greatest release available in cisco.com and you'll have the 16 IP Phones supported by default ;-)