feat: Add warning log for unsupported Weaviate server versions

Author: mpartipilo

src/Weaviate.Client.Tests/Unit/TestTypedDataClient.cs

@@ -61,6 +61,7 @@ public async Task Insert_WithValidData_CallsUnderlyingDataClient()
         // Actual insertion would require a mock/fake HTTP client
         // For now, we just verify the method signature is correct
         Assert.NotNull(typedDataClient);
+        await Task.CompletedTask;
     }
 
     [Fact]
@@ -91,6 +92,7 @@ public async Task InsertMany_WithEnumerableOfT_AcceptsCorrectType()
         // Verify the method accepts IEnumerable<T>
         Assert.NotNull(typedDataClient);
         Assert.Equal(2, articles.Count);
+        await Task.CompletedTask;
     }
 
     [Fact]
@@ -111,6 +113,7 @@ public async Task InsertMany_WithTuplesOfDataAndId_AcceptsCorrectType()
         // Verify the method accepts tuples of (T, Guid)
         Assert.NotNull(typedDataClient);
         Assert.Equal(2, requests.Count);
+        await Task.CompletedTask;
     }
 
     [Fact]
@@ -131,6 +134,7 @@ public async Task InsertMany_WithTuplesOfDataAndVectors_AcceptsCorrectType()
         // Verify the method accepts tuples of (T, Vectors)
         Assert.NotNull(typedDataClient);
         Assert.Single(requests);
+        await Task.CompletedTask;
     }
 
     [Fact]
@@ -154,6 +158,7 @@ public async Task InsertMany_WithTuplesOfDataAndReferences_AcceptsCorrectType()
         // Verify the method accepts tuples of (T, IEnumerable<ObjectReference>)
         Assert.NotNull(typedDataClient);
         Assert.Single(requests);
+        await Task.CompletedTask;
     }
 
     [Fact]

src/Weaviate.Client/WeaviateClient.cs

@@ -269,6 +269,17 @@ private async Task PerformInitializationAsync(ClientConfiguration config)
             Modules = metaDto?.Modules?.ToDictionary() ?? [],
         };
 
+        // Log warning if connecting to a server older than 1.31.0
+        var minSupportedVersion = new Version(1, 31, 0);
+        if (_metaCache.HasValue && _metaCache.Value.Version < minSupportedVersion)
+        {
+            _logger.LogWarning(
+                "Connected to Weaviate server version {ServerVersion}, which is earlier than the minimum supported version {MinVersion}. Some features may not work as expected.",
+                _metaCache.Value.Version,
+                minSupportedVersion
+            );
+        }
+
         var maxMessageSize = _metaCache?.GrpcMaxMessageSize;
 
         // Create gRPC client with metadata