Today counterparty releases version 9.55.4 which includes a hotfix for an uncaught exception which could cause a Counterparty server to stop operating normally.
There is no mandatory upgrade block for this release. However, all users are encouraged to upgrade as soon as possible.
For those running a federated node with no front-end:
fednode update counterparty counterparty-testnet
For those running a full federated node with counterwallet:
For standalone / manual installations:
pip install --upgrade counterparty-lib==9.55.4