You can update the CT law page with this info as well. Thanks.

Pistol Permit Renewals
Ninety (90) days prior to the expiration of your permit, the issuing authority will mail out a renewal letter to your last known address. The law requires that you notify the issuing authority within 48 hours of changing your address. Upon receipt of the renewal letter you can proceed to either the Special Licensing and Firearms Unit (SLFU) main office at State Police Headquarters, 1111 Country Club Road, Middletown, CT or a satellite location set up at Troop C in Tolland, Troop D in Danielson, Troop E in Montville, Troop G in Bridgeport and Troop L in Litchfield to process your renewal. An updated photo and your signature will be collected. You are required to bring positive photo identification with you. Directions to these facilities and business hours are posted below. The cost of renewing a state pistol permit is $35.00 payable to the Department of Public Safety in the form of a check or money order. Cash is not accepted. Applicants must provide proof of citizenship, such as a birth certificate, voters registration card or U.S. Passport or Naturalization papers. Legal Alien Residents must provide Alien Registration numbers and 90-day proof of residency. Please use link for additional instructions: DPS-769-C Instructions to Applicants & Photo Pistol Permit Schedule

If you lose your renewal letter or fail to receive a letter in the mail, you may obtain a replacement form by clicking on renewal application below before going to a renewal location. State pistol permit holders are granted a 90 grace period to renew their permit. Permits expired beyond 90 days will not be renewed.
DPS: Connecticut State Pistol Permit

And here is the renewal application: http://www.ct.gov/dps/lib/dps/specia.../dps-129-c.pdf