UpStare version UPSTARE_RELEASE_0-9-12 fixes a critical issue in the runtime in determining which children have died and should be ignored when coordinating an update with children. It also handles as non-blocking file descriptors created with open() and pipe(), and calls to select() with a pointer (possibly set to NULL) timeout argument that would block indefinitely.
With these changes the system can update PostgreSQL while multiple clients are connected to it.