This paper describes a qualitative study of retirees' social and personal practices via digital music technologies in the context of community music. We conducted a diary study, and interviewed retired community musicians who are experiencing transition to retirement. Amongst challenges due to ageing and retirement, retirees participating in community music often experience discontinuity of identity caused by the lack of social and personal support after retirement, and also report lack of interest in using new technologies. Life transition theory was used to understand retirees' perception and strategies of identity navigation, informing the design of community-oriented online music services. We deepened our understanding of retirement transitions with technologies by showing how retirees participating in community music make sense of new rules and norms after retirement. A key finding is that retirees reconstruct identities by connecting with music communities, through which they can develop an understanding of unfamiliar patterns of the retired life, and gain support musically and socially. Technologies act as 'boundary objects' for communication between digital and physical artefacts, personal and social relationships. We highlight the importance of managing artefactual and interpersonal boundaries when designing online services for individual and communities in transitions.