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 recommends using the factory-default Bühlmann GF settings for your dive mode. Shearwater's current defaults are 50/85 for recreational modes (medium conservatism) and 50/70 for technical open-circuit and closed-circuit/bailout modes. Older firmware may use the previous defaults of 40/85 for recreational modes and 30/70 for technical modes.

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.