Time series analysis is a promising approach to discover temporal patterns from time stamped, numeric data. A novel approach to apply time series analysis to discern temporal information from software version repositories is proposed. Version logs containing numeric as well as non-numeric data are represented as an item-set time series. A dynamic programming based algorithm to optimally segment an item-set time series is presented. The algorithm automatically produces a compacted item-set time series that can be analyzed to discern temporal patterns. The effectiveness of the approach is illustrated by applying to the Mozilla data set to study the change frequency and developer activity profiles. The experimental results show that the segmentation algorithm produces segments that capture meaningful information and is superior to the information content obtaining by arbitrarily segmenting time period into regular time intervals.