Assuming a normal statistical distribution of the 10^12 installations among the 3xnxm published versions, high values are obtained for any version. Embedded software is not easy to update, it is tied to hardware. Engineers hate to change it. Military engineers still love the Jovial and Ada languages. Gambling a system for a new functionality? (I suspect GE is using it in secret nuclear facilities). Each version consists of thousands of lines of code + comments. That requires to be conserved. I have updated a number of control systems and all the information found has always been very valuable to me. Now only open source is valued. But that produces some successes and quite a few failures. SQLite is high quality software. That must be protected and preserved. In addition, the US Congress praises it as a format for preserving documents. Perhaps the Forum could be packaged in a bd. At the end of each year, for example.