Dear Maintainer, I think the problem is this line in debian/rules:
export PYBUILD_AFTER_TEST=rm -rf {build_dir}/test.db {build_dir}/15 {build_dir}/statefilename.db dbm.open(filename) uses dbm.whichdb() function to determine the type of database to open [1] If the database file already exists, the whichdb() function is used to determine its type and the appropriate module is used; if it does not exist, the first submodule listed above that can be imported is used. Python 3.13 added the dbm.sqlite3 submodule as the first choice and the ".db" suffix is no longer added when opening, so the "rm..." above fails to delete "statefilename.db". This slight change solves the failure: export PYBUILD_AFTER_TEST=rm -rf {build_dir}/test.db {build_dir}/15 {build_dir}/statefilename.db {build_dir}/statefilename Please note that celery builds fine with only one Python version. Kind Regards [1] https://docs.python.org/3/library/dbm.html#module-dbm