Do I need a Foreign Expert’s Certificate Cancellation Letter for a new Z visa application?

I had previously finished my teaching contract in 2018 and returned to my home country and was only provided with a recommendation letter from my previous school.

I'm in the process of applying for a new work permit for another company in China, but they are asking for a Foreign Expert’s Certificate Cancellation Letter from my previous employer? Is this necessary if my work permit has expired 2 years ago?