Background: During the last decade, there has been an increase in studies describing use of mHealth, usingsmartphones with apps, in the healthcare system by a variety of populations. Despite this, few interventions including apps are targeting older people receiving home care. Developing mobile technology to its full potential of being interactive in real time remains a challenge. The current study is part of a larger project for identifying and managing health concerns via an app by using real-time data. The aim of the study was to describe older people’s usage of an app and to evaluate the impact of usage on aspects of health and health literacy over time.Methods: A quasi-experimental design was employed. Seventeen older people self-reported health concerns via Interaktor twice a week for 3-months and answered questionnaires at baseline, the end of the intervention and at a 6–month follow-up. Logged data on app usage and data on Sense of Coherence, Health Index, Nutrition Form for the Elderly, Geriatric Depression Scale-20, Swedish Communicative and Critical Health Literacy and Swedish Functional Health Literacy were collected and analysed using descriptive and non-parametric inferential statistics.Results: The median usage of the app as intended was 96%. Pain was one of the most reported health concerns and was also the health concern that triggered an alert (n = 33). The older people’s communicative and critical health literacy improved significantly over time. Regarding the scores of Sense of Coherence, Health Index, Nutritional Form for the Elderly, Geriatric Depression Scale-20 and Swedish Functional Health Literacy scale, there were no significant differences over time.Conclusions: The high app usage showed that an app may be a suitable tool for some older people living alone and receiving home care. The results indicate that the usage of Interaktor can support older people by significantly improving their communicative and critical health literacy. Aspects of health were not shown to be affected by the usage of the app. Further research with larger sample is needed for evaluation the effect on health literacy, andwhich aspects of health of importance to support by an app. © 2020 The Author(s).