Skip to main content

TFS Build Error CS1617: Invalid option 'latest' for /langversion; must be ISO-1, ISO-2, Default or an integer in range 1 to 6

After setting the Language version to C# latest minor version for my project, our TFS build started to fail with the following error message:

Error CS1617: Invalid option 'latest' for /langversion; must be ISO-1, ISO-2, Default or an integer in range 1 to 6

image

While looking through the build logs I noticed that the build server was still using MSBuild v14 instead of 15. I first thought that my build agents were not up to date, so I triggered an upgrade: http://bartwullems.blogspot.be/2017/09/team-foundation-serverupgrade-your.html

clip_image001

This made no difference, the used build tasks were not able to discover the newer version of MSBuild on the build server as they didn’t use VSWhere.exe yet.

In the end I decided to do an upgrade of TFS(a TFS 2017 instance) to TFS 2017 Update 3. After doing that, a new version of the Build task was available that correctly found MSBuild v15.0 and allowed me to use the new C# features. Finally!

Labels:

Popular posts from this blog

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...
Read more

DevToys–A swiss army knife for developers

As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Col...
Read more