When can a C1 license be upgraded to an A1?

[MacBella]

C1 license can be upgraded to an A1 license after holding a B2 license for 5 years and meeting the following conditions. Upgrading method: After holding a C1 license for one year, you can apply for a B2 license. After holding the B2 license for 5 years, you can then apply for an A1 license. License levels: A1: Large buses and A3, B1, B2, C1, C2, C3, C4, M A2: Tractor trucks and B1, B2, C1, C2, C3, C4, M A3: City buses and C1, C2, C3, C4 B1: Medium-sized buses and C1, C2, C3, C4, M (Medium-sized buses refer to buses with fewer than 19 seats, such as minibuses and vans) B2: Large trucks and C1, C2, C3, C4, M C1: Small cars and C2, C3 (Small cars refer to passenger vehicles with fewer than 9 seats, such as sedans) C2: Small automatic transmission cars C3: Low-speed trucks and C4 C4: Three-wheeled cars C5: Small automatic transmission passenger cars for disabled people (referring to five types of disabilities: right lower limb disability, both lower limb disabilities, hearing impairment, right thumb absence, or finger end joint absence) D: Regular three-wheeled motorcycles and E E: Regular two-wheeled motorcycles and F F: Light motorcycles M: Wheeled self-propelled machinery vehicles N: Trolleybuses P: Tramcars