Zambia is one of the more active SMS markets in Southern Africa for development sector, agricultural finance, and mobile money programs, and one where a specific carrier-level restriction catches international teams most often. MTN Zambia, the market leader, does not support dynamic alphanumeric sender IDs. A sender ID that has not been pre-registered and approved on MTN's network will generally be replaced by a generic numeric string, or may not deliver as intended. For a program targeting national reach across Zambia, that is not a technical footnote. MTN's market leadership means this requirement shapes how any program with national ambitions must be designed from the start.