time bomb
n.— «Although it’s common for software developers to code a time limit into beta releases to force users to install the final version of a product, such automated deadlines—often called “time bombs”—are supposed to be removed at the end of the beta process.» —“VMware users crippled by ‘time bomb’ snafu” by Gregg Kelzer Computerworld Aug. 18, 2008. (source: Double-Tongued Dictionary)