Although issue reports are useful, some of them can be obsolete, in that their corresponding commits are overwritten or rolled back, with the evolution of software. The obsolete issue reports can invalidate their references and descriptions, and can have far-reaching impacts on the approaches built on them. In this paper, given an issue report, we define its obsolete ratio as its modified lines that appear in the latest source files over its total modified code lines. In this paper, we build a tool called ICLINKER. It automatically relinks an issue report to its commits, and compares its modified files with the latest files to calculate the ratio. To the best of our knowledge, we conduct the first empirical study to analyze obsolete issue reports.