The older SOAP API for work items and test, will be deprecated in TFS 2020, see Deprecate SOAP
It is possible to have both TFVC and GIT in the same TFS project, and when you create a new project you set the default repository and the afterwards you can add the second one.
An important notice about this:
If you run XAML based builds, the build definitions can only use the default repository aka the one you selected when you created the TFS project.
So if you still use XAML, make sure you select the correct repository when you create the project
It is not possible to switch over. At least not officially yet….
UPDATE: MS support has a created a tool that can fix this
If you are stuck on upgrading to TFS 2018 due to the old deprecated XAML based builds, it can be a challenge to see how far you are from the goal of zero XAML builds.
The TFS team has released a security update for TFS 2015 and 2017, that fixes issues with cross-site scripting.
When you have a TFS collection that has been running for a long time, as I do, you end with a lot of shelvesets.
The drawbacks of this is of course, (minor) storage, but it also affects upgrade time.
But instead of manually delete all the old obsoleted stuff manually, Powershell rescues us.
The previous sample scripts on this blog has been about how to use Powershell through the REST API on a on-premise TFS. I’ve got some question about how to connect to Visualstudio Online (VSTS).
All the samples can be modified to connect to VSTS.