This article explains whether vCenter certificates can be renewed after the General Support period ends and provides the renewal procedure.
VMware vCenter Server 7.0
vCenter Server certificates can be renewed even after the end of the General Support period.
For example, although the General Support period for vCenter Server 7.0 has ended, you can continue to use vCert and Certificate Manager just as you did before the end of the period.
For detailed certificate renewal procedures, please refer to the following knowledge base article.
vCert - Scripted vCenter expired certificate replacement