Upgrading on mainnet fails with error Transaction was not mined within 750 seconds

Hi @superkruger,

Glad you were able to upgrade.

Thanks for the suggestion. I have created an issue: https://github.com/OpenZeppelin/openzeppelin-sdk/issues/1577

We just released Truffle Upgrades and Buidler Upgrades plugins, both of which should pickup where you left off when deploying and upgrading.

See the following for details: