Some schools stipulate this. Most students in the plan should have canceled the regulation of linking Band 4 with degree, but most schools outside the plan have this regulation, in order to control the quality of degree certificates. You must get CET-4, pass the degree exam, and there may be an average score requirement. This provision is also in accordance with relevant state regulations. However, the diploma is generally not linked to Band 4, and you can get it after completing the credits. Diploma and degree certificate are not linked.