The introduction of the new four-digit postal code system in 1979 was a significant improvement aimed at increasing the efficiency of the postal service. This stamp design, featuring a letter with the new postal code, was a practical and functional issue that helped the public adapt to the new system.

Another stamp series on Postal Codes, 6-digit Postal Code, was issued on 1 September 1995 when the 6-digit postal code was introduced, a continuous effort to improve postal services, infrastructure, and efficiency.