diff --git a/pom.xml b/pom.xml
index 9f4c81d..cbc27cf 100644
--- a/pom.xml
+++ b/pom.xml
@@ -15,14 +15,14 @@
         <junit.version>4.13.2</junit.version>
         <junit-jupiter.version>5.10.1</junit-jupiter.version>
         <junit-platform.version>1.10.1</junit-platform.version>
-        <kotlin.version>1.9.21</kotlin.version>
+        <kotlin.version>1.9.24</kotlin.version>
         <kotest.version>5.7.2</kotest.version>
         <joda.version>2.9</joda.version>
-        <detekt.version>1.23.4</detekt.version>
+        <detekt.version>1.23.5</detekt.version>
         <carrotsearch.version>0.7.0</carrotsearch.version>
         <arrow-memory-netty.version>12.0.1</arrow-memory-netty.version>
     </properties>
-    <version>0.12.0-SNAPSHOT</version>
+    <version>0.12.2-SNAPSHOT</version>
     <name>dremio-udf-gis</name>
     <description>GIS UDF extensions for Dremio</description>
     <url>https://github.com/sheinbergon/dremio-udf-gis</url>
diff --git a/src/main/java/org/sheinbergon/dremio/udf/gis/STIsSimple.java b/src/main/java/org/sheinbergon/dremio/udf/gis/STIsSimple.java
index 34b6c71..678907b 100644
--- a/src/main/java/org/sheinbergon/dremio/udf/gis/STIsSimple.java
+++ b/src/main/java/org/sheinbergon/dremio/udf/gis/STIsSimple.java
@@ -39,7 +39,7 @@ public void setup() {
   public void eval() {
     if (org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.isHolderSet(binaryInput)) {
       org.locationtech.jts.geom.Geometry geom = org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.toGeometry(binaryInput);
-      boolean result = geom.isSimple();
+      boolean result = org.locationtech.jts.operation.valid.IsSimpleOp.isSimple(geom);
       org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.setBooleanValue(output, result);
     } else {
       org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.markHolderNotSet(output);
diff --git a/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplify.java b/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplify.java
index 6a85a03..b05af9b 100644
--- a/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplify.java
+++ b/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplify.java
@@ -21,7 +21,6 @@
 import com.dremio.exec.expr.annotations.FunctionTemplate;
 import com.dremio.exec.expr.annotations.Output;
 import com.dremio.exec.expr.annotations.Param;
-import org.apache.arrow.memory.ArrowBuf;
 
 import javax.inject.Inject;
 
@@ -31,25 +30,29 @@
     nulls = FunctionTemplate.NullHandling.INTERNAL,
     costCategory = FunctionTemplate.FunctionCostCategory.COMPLEX)
 public class STSimplify implements SimpleFunction {
+
   @Param
   org.apache.arrow.vector.holders.NullableVarBinaryHolder binaryInput;
 
-  @Param(constant = true)
+  @Param
   org.apache.arrow.vector.holders.Float8Holder toleranceInput;
 
   @Output
   org.apache.arrow.vector.holders.NullableVarBinaryHolder binaryOutput;
 
   @Inject
-  ArrowBuf buffer;
+  org.apache.arrow.memory.ArrowBuf buffer;
 
   public void setup() {
   }
 
   public void eval() {
     if (org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.isHolderSet(binaryInput)) {
+      double tolerance = toleranceInput.value;
       org.locationtech.jts.geom.Geometry geom = org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.toGeometry(binaryInput);
-      org.locationtech.jts.geom.Geometry simplified = org.locationtech.jts.simplify.DouglasPeuckerSimplifier.simplify(geom, toleranceInput.value);
+      org.locationtech.jts.simplify.DouglasPeuckerSimplifier simplifier = new org.locationtech.jts.simplify.DouglasPeuckerSimplifier(geom);
+      simplifier.setDistanceTolerance(tolerance);
+      org.locationtech.jts.geom.Geometry simplified = simplifier.getResultGeometry();
       simplified.setSRID(geom.getSRID());
       byte[] bytes = org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.toEWKB(simplified);
       buffer = buffer.reallocIfNeeded(bytes.length);
@@ -58,4 +61,4 @@ public void eval() {
       org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.markHolderNotSet(binaryOutput);
     }
   }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplifyPreserveTopology.java b/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplifyPreserveTopology.java
new file mode 100644
index 0000000..3730cb1
--- /dev/null
+++ b/src/main/java/org/sheinbergon/dremio/udf/gis/STSimplifyPreserveTopology.java
@@ -0,0 +1,63 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.sheinbergon.dremio.udf.gis;
+
+import com.dremio.exec.expr.SimpleFunction;
+import com.dremio.exec.expr.annotations.FunctionTemplate;
+import com.dremio.exec.expr.annotations.Output;
+import com.dremio.exec.expr.annotations.Param;
+
+import javax.inject.Inject;
+
+@FunctionTemplate(
+    name = "ST_SimplifyPreserveTopology",
+    scope = FunctionTemplate.FunctionScope.SIMPLE,
+    nulls = FunctionTemplate.NullHandling.INTERNAL,
+    costCategory = FunctionTemplate.FunctionCostCategory.COMPLEX)
+public class STSimplifyPreserveTopology implements SimpleFunction {
+
+  @Param
+  org.apache.arrow.vector.holders.NullableVarBinaryHolder binaryInput;
+
+  @Param
+  org.apache.arrow.vector.holders.Float8Holder toleranceInput;
+
+  @Output
+  org.apache.arrow.vector.holders.NullableVarBinaryHolder binaryOutput;
+
+  @Inject
+  org.apache.arrow.memory.ArrowBuf buffer;
+
+  public void setup() {
+  }
+
+  public void eval() {
+    if (org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.isHolderSet(binaryInput)) {
+      double tolerance = toleranceInput.value;
+      org.locationtech.jts.geom.Geometry geom = org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.toGeometry(binaryInput);
+      org.locationtech.jts.simplify.TopologyPreservingSimplifier simplifier = new org.locationtech.jts.simplify.TopologyPreservingSimplifier(geom);
+      simplifier.setDistanceTolerance(tolerance);
+      org.locationtech.jts.geom.Geometry result = simplifier.getResultGeometry();
+      byte[] bytes = org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.toEWKB(result);
+      buffer = buffer.reallocIfNeeded(bytes.length);
+      org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.populate(bytes, buffer, binaryOutput);
+    } else {
+      org.sheinbergon.dremio.udf.gis.util.GeometryHelpers.markHolderNotSet(binaryOutput);
+    }
+  }
+}
\ No newline at end of file
diff --git a/src/test/kotlin/org/sheinbergon/dremio/udf/gis/STSimplifyPreserveTopologyTests.kt b/src/test/kotlin/org/sheinbergon/dremio/udf/gis/STSimplifyPreserveTopologyTests.kt
new file mode 100644
index 0000000..b2675d1
--- /dev/null
+++ b/src/test/kotlin/org/sheinbergon/dremio/udf/gis/STSimplifyPreserveTopologyTests.kt
@@ -0,0 +1,51 @@
+package org.sheinbergon.dremio.udf.gis
+
+import org.apache.arrow.vector.holders.Float8Holder
+import org.apache.arrow.vector.holders.NullableVarBinaryHolder
+import org.sheinbergon.dremio.udf.gis.spec.GeometryProcessingFunSpec
+import org.sheinbergon.dremio.udf.gis.util.allocateBuffer
+import org.sheinbergon.dremio.udf.gis.util.reset
+
+internal class STSimplifyPreserveTopologyTests : GeometryProcessingFunSpec<STSimplifyPreserveTopology>() {
+
+  init {
+
+    beforeEach {
+      function.toleranceInput.reset()
+    }
+
+    testGeometryProcessing(
+      name = "Calling ST_SimplifyPreserveTopology on a MULTILINESTRING with a tolerance of 40.0",
+      wkt = """
+        MULTILINESTRING (
+          (20 180, 20 150, 50 150, 50 100, 110 150, 150 140, 170 120), 
+          (20 10, 80 30, 90 120), 
+          (90 120, 130 130), 
+          (130 130, 130 70, 160 40, 180 60, 180 90, 140 80), 
+          (50 40, 70 40, 80 70, 70 60, 60 60, 50 50, 50 40) 
+      )""".trimIndent(),
+      expected = """
+        MULTILINESTRING(
+          (20 180,50 100,110 150,170 120),
+          (20 10,90 120),
+          (90 120,130 130),
+          (130 130,130 70,160 40,180 90,140 80),
+          (50 40,70 40,80 70,60 60,50 40)
+        )""".trimIndent()
+    ) { function.toleranceInput.value = 40.0 }
+
+    testNullGeometryProcessing(
+      "Calling ST_SimplifyPreserveTopology on a NULL input"
+    )
+  }
+
+  override val function = STSimplifyPreserveTopology().apply {
+    binaryInput = NullableVarBinaryHolder()
+    toleranceInput = Float8Holder()
+    binaryOutput = NullableVarBinaryHolder()
+    buffer = allocateBuffer()
+  }
+
+  override val STSimplifyPreserveTopology.wkbInput: NullableVarBinaryHolder get() = function.binaryInput
+  override val STSimplifyPreserveTopology.wkbOutput: NullableVarBinaryHolder get() = function.binaryOutput
+}