We have upgraded the contracts on the Mumbai testnet wrt to Checkpoints Optimizations. All those who are running nodes on the Mumbai Testnet, please ensure that you are upgrading your nodes as well.
Please follow the instructions below
git checkout v0.2.1-mumbai
sudo service heimdalld restart
sudo service heimdalld-rest-server restart
sudo service heimdalld-bridge restart
Please let us know if you face any issues while upgrading.