By an "external data file", I mean that the package keeps a runtime database in a disk file or something, and will end up getting confused if two versions are r

By an "external data file", I mean that the package keeps a runtime database in a disk file or something, and will end up getting confused if two versions are reading and writing that file concurrently. The same would apply if the two versions had any way to end up sharing an in-memory data structure as well.