The short answer is you do NOT need the upgrade.

VPM and DCIEM are additional decompression models available on some Shearwater dive computers as an optional alternative to the default Bühlmann GF gas content model used by all Shearwater dive computers (and most other dive computers) to compute no-decompression limits and decompression schedules for dives. For recreational diving, there is no expert consensus that VPM or DCIEM is better than Bühlmann. If you don't understand the differences and why you would choose one or the other, Dive Gear Express and Shearwater recommends sticking with the factory default of Bühlmann 30/70.

Avelo Mode allows a Recreational Avelo Diver using the Avelo Dive System equipment to gain easy visibility of their Avelo dive data and ensure accurate gas time remaining on the Teric dive computer when also paired with a SWIFT transmitter.