The easiest way to determine the generation is by the frame number.
SUSHI BIKE 1st generation (production period: 2019 to 2021).
Frame number always starts with the letters "SU".
SUSHI BIKE +models (production period: 2021 to 2023)
Frame number starts with either "SB", "AI" or "22".
Check out the following help article for assistance: Determine frame number
SUSHI BIKE 3.0 (Production period: 2023 onwards)
Frame number starts with either "SM" or "SC".
Check out the following help article for assistance: Where can I find the frame number on the new SUSHI BIKE 3.0?