Working memory updating (updating) and working memory capacity (WMC) have been assumed to share a common mechanism. However, it is unclear whether WMC can be expanded by boosting the efficiency of updating, particularly during late adulthood. In this randomized controlled study, 33 older adults (aged 60 years and above, M = 69.53, SD = 5.21) were assigned to updating training (n = 17) and contact control (n = 16) groups. In the training group, updating was targeted by a running memory task and a chess game in each training session; whereas in the control group, motivational effects were estimated by their attendance to a series of mental health-related lectures. The boosted updating efficiency was demonstrated by direct training gains over sessions on updating criterion/training tasks, and significant frontocentral inflation at the N2 time range. Near transfer effects were revealed on untrained similar measures immediately after training and partly maintained at a 3-month follow-up. Far transfer effects to WMC were revealed by a significant increase in contralateral delay activity (CDA) ERP measures, although these effects did not manifest on WMC span tasks and other far transfer measures. Note that increased CDA was significantly correlated with the extent of direct gains in updating training. Our findings suggest that updating efficiency can be boosted in older adults; although it has not yet brought about an explicit expansion of WMC in our behavioral measures (i.e., on span tasks), capacity-related neural changes (i.e., on CDA) have nevertheless, started to show up in our short-term updating training program.