A Michigan CPL is eligible for renewal from 6 months before your license expires and up to one year after it expires. MCL 28.425l
The county clerk (where your CPL was issued) shall notify a licensee that a license is about to expire and may be renewed by mail to the last known address of the licensee as shown on the records of the county clerk.
If you did not receive the renewal letter, you can either contact your county clerk, the state police CPL Unit by email MSPCPL@michigan.gov or phone 517-284-3700 to obtain your pin for online renewal.
You can also print the application and mail it directly to the Michigan State Police Concealed Pistol License Unit, P.O. Box 30634, Lansing, Michigan 48909, along with a check or money order made payable to the “State of Michigan”.
If the license has expired for more than 12 months, then you will have to re-apply as if you never had a CPL (and a new training certificate is required).
When you renew before your expiration date your permit is automatically extended 5 years with no wait.
When you renew after expiration, you can not carry concealed until you get your new CPL, or 30 days after submitting your renewal (with the receipt) whichever comes first. MCL 28.425l(4)(e)