From the Town of Londonderry:

Did you miss registering your dog by the Town’s April 30th deadline? Don’t worry, you still have time before faces possible fines and violation notices! The Town of Londonderry extended the dog registration year until June 30.
To avoid a fine and violation notice, please make sure to update your dog’s vaccinations and register them by following this link:
https://www.londonderrynh.org/town…/pages/dog-licenses
You can even register them online!