Upgrading to 17.09 - DTR Tags could not be determined

Expected behavior

Upgrade from 17.06.2 CE to 17.09.0 CE to pass successful.

Actual behavior

$ upgrade.sh 17.09-latest
17.09-latest: Pulling from docker4x/upgrade-azure
Digest: sha256:534d270b2d9c054b7b461d36527df6922ff1769f5a561cc1758261ed322c73b0
Status: Image is up to date for docker4x/upgrade-azure:17.09-latest
Execute upgrade container for 17.09-latest
Copying upgrade scripts …
DTR Tags could not be determined based on DTR containers that are running:
Please pass in the DTR version installed using DTR_VERSION parameter

Additional Information

To pass this parameter I need to open a shell in the upgrade-azure container and pass it to the upgrade-azure-core container, which then fails with another error.

We found an issue and will fix this shortly.