Student absenteeism has remained high following the COVID-19 pandemic and districts need low-cost strategies to improve attendance. In 2020-21, the National Center for Rural Education Research Networks piloted a promising personalized messaging intervention in 8 rural districts in New York and Ohio. We worked with a student information system provider to replicate the intervention in a randomized trial in 47 districts in 16 states between 2022-23 and 2023-24. We find that the personalized messages reduced student absences by between 1.7 (p<0.05) and 4.5 percent (p<0.05) and cost, on average, $4.07 per student to implement. We report on implementation challenges and heterogeneous effects across student populations. Our findings have practical implications for implementing technology-based interventions in the rural context.