Well, your question is very representative. Indeed, before this, there was no principal's signature on the admission notice, but some universities did.

According to the "Notice of the Ministry of Education on Doing a Good Job of Enrollment in Colleges and Universities in 20 14" (Church [20 14] 1No.) and the Notice of the General Office of the Ministry of Education on Doing a Good Job of Enrollment in Colleges and Universities in 20 14 "(Church [2014)

After all, the document has just been issued, and it will be gone this year. In the future, the admission notice will be signed, and the system will gradually form.