How many subjects need to be retaken to upgrade from C1 to B2?

[LaJoshua]

C1 to B2 upgrade requires passing four subjects. You need to start from Subject 1 again. The contents of Subject 1, Subject 3, and Subject 4 remain unchanged, which are the theoretical test, road test, and safe civilized driving test respectively. Subject 2 content: stake test, slope fixed-point parking and starting, parallel parking, single-plank bridge passing, curve driving, right-angle turning, limited-width gate passing, continuous obstacle passing, bumpy road driving, narrow road U-turn, as well as simulated highway driving, continuous sharp turns on mountain roads, tunnels, rain (fog) conditions, slippery roads, and emergency handling. Conditions for upgrading from C1 to B2 driver's license: Age between 20 and 60 years old; Height not less than 155cm; Holding a C1 driver's license for more than 1 year; No record of accumulating 12 penalty points in the current scoring cycle and the most recent scoring cycle before application; Visual acuity must reach 5.0 or above on the logarithmic visual acuity chart; No record of drunk driving or causing a traffic accident with casualties while being primarily responsible during the period of holding a C1 driver's license.