日前做CUCM升级操作时，遇到如下报错
"Upgrades are prohibited during Licensing GracePeriod"，经过资料查找及自己摸索，发现有两个办法可以解决此问题：
问题现象：
After Disaster Recovery System (DRS) backup is done onthe old server, we DRS restore all the data into the newly replaced server. Thelicense file for old server is valid for 30 days.
During license grace period, you can not proceed due tothe upgrade error message "Upgrades are prohibited during License GracePeriod".
If this error message is seen during a jump upgrade to9.1(2) see CSCuj10105.
解决办法：
方法一：
此方法是思科给出的解决办法，方法如下：
If license is uploaded before DRS restore then use thefollowing steps to correct the state of licensing on the system:
1. Remove the rehosted (new) license files using clicommond "file delete xxx.lic"
2. Restart license manager.
3. Re-upload the rehosted (new) license files.
方法二：
既然明确知道此报错是由于license的问题，那么我们是否可以导入一个demo license呢？答案是可以；测试通过！