diff --git a/release-version-sane/UpstreamRelease.cs b/release-version-sane/UpstreamRelease.cs
new file mode 100644
index 0000000..71e516d
--- /dev/null
+++ b/release-version-sane/UpstreamRelease.cs
@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Newtonsoft.Json;
+
+namespace ReleaseVersionSane
+{
+    public class UpstreamRelease
+    {
+        private readonly Uri RELEASE_INDEX = new Uri("https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases-index.json");
+
+        public async Task<(List<string> sdks, string runtime)> GetLatestRelease(HttpClient client, string majorMinor)
+        {
+            var releaseIndexRawJson = await client.GetStringAsync(RELEASE_INDEX);
+            var releaseInfoChannelJsonUrl = GetReleaseInfoChannelUrl(releaseIndexRawJson, majorMinor);
+            if (releaseInfoChannelJsonUrl == null)
+            {
+                return (null, null);
+            }
+
+            var releaseInfoChannelRawJson = await client.GetStringAsync(releaseInfoChannelJsonUrl);
+            return GetLatestVersion(releaseInfoChannelRawJson);
+        }
+
+        private (List<string> sdks, string runtime) GetLatestVersion(string releaseRawJson)
+        {
+            dynamic releaseChannel = JsonConvert.DeserializeObject(releaseRawJson);
+
+            string runtime = null;
+            var sdks = new List<string>();
+            var latestDate = new DateTime(2000, 1, 1);
+
+            foreach (var release in releaseChannel["releases"])
+            {
+                if (!DateTime.TryParse((string)release["release-date"], out DateTime releaseDate))
+                {
+                    continue;
+                }
+
+                if (releaseDate > latestDate)
+                {
+                    latestDate = releaseDate;
+                    runtime = release["runtime"]["version"];
+                    sdks = new List<string>();
+                    foreach (var sdk in release["sdks"])
+                    {
+                        sdks.Add((string)sdk["version"]);
+                    }
+                }
+            }
+
+            return (sdks, runtime);
+        }
+
+        private Uri GetReleaseInfoChannelUrl(string releaseIndexRawJson, string majorMinor)
+        {
+            dynamic releaseIndex = JsonConvert.DeserializeObject(releaseIndexRawJson);
+
+            string releaseChannelJsonUrl = null;
+            foreach (var release in releaseIndex["releases-index"])
+            {
+                if (release["channel-version"] == majorMinor)
+                {
+                    releaseChannelJsonUrl = release["releases.json"];
+                    break;
+                }
+            }
+
+            return new Uri(releaseChannelJsonUrl);
+        }
+
+    }
+}
diff --git a/release-version-sane/VersionTest.cs b/release-version-sane/VersionTest.cs
new file mode 100644
index 0000000..2b3161c
--- /dev/null
+++ b/release-version-sane/VersionTest.cs
@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net.Http;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Diagnostics;
+using Xunit;
+
+namespace ReleaseVersionSane
+{
+    public class VersionTest
+    {
+        [Fact]
+        public async Task VersionIsSane()
+        {
+            var upstream = new UpstreamRelease();
+            var currentRuntimeVersion = GetRuntimeVersion();
+            var currentSdkVersion = GetSdkVersion();
+
+            string majorMinor = $"{currentRuntimeVersion.Major}.{currentRuntimeVersion.Minor}";
+            (List<string> publicSdkVersions, string publicRuntimeVersion) = await upstream.GetLatestRelease(new HttpClient(), majorMinor);
+
+            bool currentVersionNewerThanPublic = false;
+
+            if (publicRuntimeVersion != currentRuntimeVersion.ToString())
+            {
+                currentRuntimeVersion = new Version(currentRuntimeVersion.Major,
+                                                    currentRuntimeVersion.Minor,
+                                                    currentRuntimeVersion.Build - 1);
+                Assert.Equal(currentRuntimeVersion.ToString(), publicRuntimeVersion);
+                currentVersionNewerThanPublic = true;
+            }
+
+            if (currentVersionNewerThanPublic)
+            {
+                currentSdkVersion = new Version(currentSdkVersion.Major,
+                                                currentSdkVersion.Minor,
+                                                currentSdkVersion.Build - 1);
+            }
+
+            bool sdkMatched = false;
+            foreach (var sdk in publicSdkVersions)
+            {
+                if (sdk == currentSdkVersion.ToString())
+                {
+                    sdkMatched = true;
+                    break;
+                }
+            }
+
+            Assert.True(sdkMatched);
+        }
+
+        private Version GetRuntimeVersion()
+        {
+            int exitCode = RunProcessAndGetOutput(new string[] { "dotnet" , "--list-runtimes" }, out string result);
+            if (exitCode != 0)
+            {
+                return null;
+            }
+
+            return new Version(result
+                              .Split(Environment.NewLine)
+                              .Where(line => line.StartsWith("Microsoft.NETCore.App "))
+                              .Select(line => line.Split(' ')[1])
+                              .First());
+
+        }
+
+        private Version GetSdkVersion()
+        {
+            int exitCode = RunProcessAndGetOutput(new string[] { "dotnet" , "--list-sdks" }, out string result);
+            if (exitCode != 0)
+            {
+                return null;
+            }
+
+            return new Version(result
+                              .Split(Environment.NewLine)
+                              .Select(line => line.Split(' ')[0])
+                              .First());
+
+        }
+
+
+        private static int RunProcessAndGetOutput(string[] processAndArguments, out string standardOutput)
+        {
+            ProcessStartInfo startInfo = new ProcessStartInfo();
+            startInfo.FileName = processAndArguments[0];
+            startInfo.Arguments = string.Join(" ", processAndArguments.Skip(1));
+            startInfo.RedirectStandardOutput = true;
+
+            using (Process p = Process.Start(startInfo))
+            {
+                p.WaitForExit();
+                using (StreamReader r = p.StandardOutput)
+                {
+                    standardOutput = r.ReadToEnd();
+                }
+                return p.ExitCode;
+            }
+        }
+
+    }
+}
diff --git a/release-version-sane/release-version-sane.csproj b/release-version-sane/release-version-sane.csproj
new file mode 100644
index 0000000..d4dcc01
--- /dev/null
+++ b/release-version-sane/release-version-sane.csproj
@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="$(MicrosoftNetTestSdkVersion)" />
+    <PackageReference Include="xunit" Version="$(XunitVersion)" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="$(XunitRunnerVisualStudioVersion)" />
+  </ItemGroup>
+
+</Project>
diff --git a/release-version-sane/test.json b/release-version-sane/test.json
new file mode 100644
index 0000000..96a8393
--- /dev/null
+++ b/release-version-sane/test.json
@@ -0,0 +1,12 @@
+{
+  "name": "release-version-sane",
+  "enabled": true,
+  "requiresSdk": true,
+  "version": "3.1",
+  "versionSpecific": false,
+  "type": "xunit",
+  "cleanup": true,
+  "ignoredRIDs":[
+
+  ]
+}