diff --git a/.github/workflows/publish-nuget-packages.yaml b/.github/workflows/publish-nuget-packages.yaml
index 48e2b30..f3b49bc 100644
--- a/.github/workflows/publish-nuget-packages.yaml
+++ b/.github/workflows/publish-nuget-packages.yaml
@@ -8,10 +8,10 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
-    - uses: actions/setup-dotnet@v1
+    - uses: actions/checkout@v4
+    - uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '6.0.x'
+        dotnet-version: '8.0.x'
     - run: |
         echo "Github ref is ${GITHUB_REF}"
         arrTag=(${GITHUB_REF//\// })
diff --git a/.github/workflows/run-tests.yaml b/.github/workflows/run-tests.yaml
index 9b10467..e2185a0 100644
--- a/.github/workflows/run-tests.yaml
+++ b/.github/workflows/run-tests.yaml
@@ -9,13 +9,13 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - name: Setup .NET Core 3.1	
-      uses: actions/setup-dotnet@v1	
-      with:	
-        dotnet-version: 3.1.x
     - name: Setup .NET Core 6.0
-      uses: actions/setup-dotnet@v1
+      uses: actions/setup-dotnet@v4
       with:
         dotnet-version: '6.0.x'
-    - uses: actions/checkout@v1
+    - name: Setup .NET Core 8.0
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '8.0.x'
+    - uses: actions/checkout@v4
     - run: dotnet test -c "Debug"
\ No newline at end of file
diff --git a/src/PromQL.Parser/Functions.cs b/src/PromQL.Parser/Functions.cs
index de8c0d1..eb10934 100644
--- a/src/PromQL.Parser/Functions.cs
+++ b/src/PromQL.Parser/Functions.cs
@@ -9,7 +9,7 @@ public static class Functions
         /// </summary>
         /// <remarks>
         /// Primarily taken from https://github.com/prometheus/prometheus/blob/main/web/ui/module/codemirror-promql/src/grammar/promql.grammar#L121-L188.
-        /// More authoritative source would be https://github.com/prometheus/prometheus/blob/7471208b5c8ff6b65b644adedf7eb964da3d50ae/promql/parser/functions.go.
+        /// More authoritative source would be https://github.com/prometheus/prometheus/blob/38fd48e6b54b5413b5281efbeeb989a44845be34/promql/parser/functions.go.
         /// </remarks>
         public static ImmutableDictionary<string, Function> Map { get; set; } = new[]
         {
@@ -34,15 +34,23 @@ public static class Functions
             new Function("days_in_month", ValueType.Vector, varadicModifier: 1 , ValueType.Vector),
             new Function("day_of_month", ValueType.Vector, varadicModifier: 1, ValueType.Vector),
             new Function("day_of_week", ValueType.Vector, varadicModifier: 1, ValueType.Vector),
+            new Function("day_of_year", ValueType.Vector, varadicModifier: 1, ValueType.Vector),
             new Function("deg", ValueType.Vector, ValueType.Vector),
             new Function("delta", ValueType.Vector, ValueType.Matrix),
             new Function("deriv", ValueType.Vector, ValueType.Matrix),
             new Function("exp", ValueType.Vector, ValueType.Vector),
             new Function("floor", ValueType.Vector, ValueType.Vector),
+            new Function("histogram_avg", ValueType.Vector, ValueType.Vector),
+            new Function("histogram_count", ValueType.Vector, ValueType.Vector),
+            new Function("histogram_sum", ValueType.Vector, ValueType.Vector),
+            new Function("histogram_stddev", ValueType.Vector, ValueType.Vector),
+            new Function("histogram_stdvar", ValueType.Vector, ValueType.Vector),
+            new Function("histogram_fraction", ValueType.Vector, ValueType.Scalar, ValueType.Scalar, ValueType.Vector),
             new Function("histogram_quantile", ValueType.Vector, ValueType.Scalar, ValueType.Vector),
-            new Function("holt_winters", ValueType.Vector, ValueType.Matrix, ValueType.Scalar, ValueType.Scalar),
+            new Function("double_exponential_smoothing", ValueType.Vector, ValueType.Matrix, ValueType.Scalar, ValueType.Scalar),
             new Function("hour", ValueType.Vector, varadicModifier: 1, ValueType.Vector),
             new Function("idelta", ValueType.Vector, ValueType.Matrix),
+            new Function("info", ValueType.Vector, varadicModifier: 1, ValueType.Vector, ValueType.Vector),
             new Function("increase", ValueType.Vector, ValueType.Matrix),
             new Function("irate", ValueType.Vector, ValueType.Matrix),
             new Function("label_replace", ValueType.Vector, ValueType.Vector, ValueType.String, ValueType.String, ValueType.String, ValueType.String),
@@ -51,6 +59,7 @@ public static class Functions
             new Function("ln", ValueType.Vector, ValueType.Vector),
             new Function("log_10", ValueType.Vector, ValueType.Vector),
             new Function("log_2", ValueType.Vector, ValueType.Vector),
+            new Function("mad_over_time", ValueType.Vector, ValueType.Matrix),
             new Function("max_over_time", ValueType.Vector, ValueType.Matrix),
             new Function("min_over_time", ValueType.Vector, ValueType.Matrix),
             new Function("minute", ValueType.Vector, varadicModifier: 1, ValueType.Vector),
@@ -69,6 +78,8 @@ public static class Functions
             new Function("sinh", ValueType.Vector, ValueType.Vector),
             new Function("sort", ValueType.Vector, ValueType.Vector),
             new Function("sort_desc", ValueType.Vector, ValueType.Vector),
+            new Function("sort_by_label", ValueType.Vector, varadicModifier: 0, ValueType.Vector, ValueType.String),
+            new Function("sort_by_label_desc", ValueType.Vector, varadicModifier: 0, ValueType.Vector, ValueType.String),
             new Function("sqrt", ValueType.Vector, ValueType.Vector),
             new Function("stddev_over_time", ValueType.Vector, ValueType.Matrix),
             new Function("stdvar_over_time", ValueType.Vector, ValueType.Matrix),
diff --git a/src/PromQL.Parser/Operators.cs b/src/PromQL.Parser/Operators.cs
index 8e6182d..7f9b546 100644
--- a/src/PromQL.Parser/Operators.cs
+++ b/src/PromQL.Parser/Operators.cs
@@ -137,7 +137,9 @@ public enum Unary
             new AggregateOperator("topk", ValueType.Scalar),
             new AggregateOperator("bottomk", ValueType.Scalar),
             new AggregateOperator("count_values", ValueType.String),
-            new AggregateOperator("quantile", ValueType.Scalar)
+            new AggregateOperator("quantile", ValueType.Scalar),
+            new AggregateOperator("limitk", ValueType.Scalar),
+            new AggregateOperator("limit_ratio", ValueType.Scalar)
         }.ToImmutableDictionary(k => k.Name, v => v, StringComparer.OrdinalIgnoreCase);
 
         public static string ToPromQl(this Operators.Binary op) => op switch
diff --git a/src/PromQL.Parser/PromQL.Parser.csproj b/src/PromQL.Parser/PromQL.Parser.csproj
index c1f7d75..d140b24 100644
--- a/src/PromQL.Parser/PromQL.Parser.csproj
+++ b/src/PromQL.Parser/PromQL.Parser.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFrameworks>netcoreapp3.1;net6.0</TargetFrameworks>
+        <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
         <LangVersion>10</LangVersion>
         <Nullable>enable</Nullable>
         <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
diff --git a/tests/PromQL.Parser.Tests/ParserTests.cs b/tests/PromQL.Parser.Tests/ParserTests.cs
index 59a5afa..831e4e7 100644
--- a/tests/PromQL.Parser.Tests/ParserTests.cs
+++ b/tests/PromQL.Parser.Tests/ParserTests.cs
@@ -383,11 +383,26 @@ public void FunctionCall_InvalidParameterCountVaradic()
         [TestCase("hour()")]
         [TestCase("hour(one)")]
         [TestCase("hour(one, two)")]
-        [TestCase("label_join(instant_vector, 'dst_label', 'separator', 'one', 'two')")]
-        public void FunctionCall_Varadic(string query)
+        public void FunctionCall_Varadic_One(string query)
         {
             Parse(Parser.Expr, query).Should().BeOfType<FunctionCall>();
         }
+        
+        [Test]
+        public void FunctionCall_Varadic_Label_Join()
+        {
+            var exp = Parse(Parser.Expr, "label_join(instant_vector, 'dst_label', 'separator', 'one', 'two')").Should().BeOfType<FunctionCall>().Subject;
+            exp.Args.Should().HaveCount(5);
+        }
+        
+        [Test]
+        [TestCase("sort_by_label(my_metric, 'one', 'two', 'three')")]
+        [TestCase("sort_by_label_desc(my_metric, 'one', 'two', 'three')")]
+        public void FunctionCall_Varadic_Sort(string query)
+        {
+            var exp = Parse(Parser.Expr, query).Should().BeOfType<FunctionCall>().Subject;
+            exp.Args.Should().HaveCount(4);
+        }
 
         [Test]
         public void FunctionCall_OneArg() => Parse(Parser.Expr, "abs (1)")
@@ -850,6 +865,8 @@ public void BinaryExpr_BoolNonComparison(string query)
         [TestCase("stdvar (blah)", "stdvar")]
         [TestCase("sum (blah)", "sum")]
         [TestCase("topk (1, blah)", "topk")]
+        [TestCase("limitk (1, blah)", "limitk")]
+        [TestCase("limit_ratio (1, blah)", "limit_ratio")]
         public void AggregateExpr_Operator(string input, string expected) => Parse(Parser.AggregateExpr, input)
             .Operator.Name.Should().Be(expected);
 
diff --git a/tests/PromQL.Parser.Tests/PromQL.Parser.Tests.csproj b/tests/PromQL.Parser.Tests/PromQL.Parser.Tests.csproj
index 7ade3d5..2c19004 100644
Binary files a/tests/PromQL.Parser.Tests/PromQL.Parser.Tests.csproj and b/tests/PromQL.Parser.Tests/PromQL.Parser.Tests.csproj differ