An optimized series interconnection process can provide many benefits for the manufacture of thin-film PV including lower panel transit times, lower capital equipment costs, smaller line foot print and less panel area wasted. The One Step Interconnect (OSI) process has been previously introduced 1. It utilizes conventional laser scribing and inkjet additive manufacture to form the series interconnect. Good electrical performance has previously been achieved on CdTe mini-modules. Here the latest developments are presented. Further mini-module electrical results are shown with Fill Factors (FFs) of, on average, 70% and up to 80%. No loss of fill factor is seen as cells are connected in series. An extensive lifetime testing program is now underway. An encapsulation process has been found and verified using the IEC 61646 standard damp heat test for packaging integrity. Over 400 hours of thermal cycling has been completed on OSI interconnected modules with no degradation in power output.