Sometimes counterparty-lib can be updated or even reinstalled, but due to some Python module bugs the old version can remain lurking around.
$ sudo pip3 list | grep counterparty-lib [sudo] password for xcp: counterparty-lib (9.52.0) $ counterparty-server start [INFO] Running v1.1.1 of counterparty-server. [INFO] Running v9.51.4 of counterparty-lib. [INFO] Acquiring lock.
One workaround is to force upgrade the package:
sudo pip3 install --force --upgrade counterparty-lib