Pivotal Cloud Foundry® (PCF) Elastic Runtime Version 1.8.x when upgraded to 1.9.x
After upgrading from Elastic Runtime 1.8.x to 1.9x, the output of `cf buildpacks` shows that there are two versions of the .NET Core buildpack installed. One is called `dotnet-core-buildpack` while the other one is called `dotnet_core_buildpack.`
This is a known issue when upgrading from ERT 1.8 to 1.9. The name of the .NET Core build pack has changed, and this results in both the older and newer version of the build pack being present after the upgrade.
The resolution is simple. Delete the older version of the build pack. In ERT 1.8, the build pack was called `dotnet-core-buildpack` and in ERT 1.9, it is called `dotnet_core_buildpack.` Note how the old build pack name has a dash in it while the new buildpack has underscores instead of the dashes. You can delete the old version by running `cf delete-buildpack dotnet-core-buildpack` as a platform administrator.