diff --git a/src/main/java/de/rwth/idsg/steve/ocpp/ws/JsonObjectMapper.java b/src/main/java/de/rwth/idsg/steve/ocpp/ws/JsonObjectMapper.java
index 26d54d867..a379eb629 100644
--- a/src/main/java/de/rwth/idsg/steve/ocpp/ws/JsonObjectMapper.java
+++ b/src/main/java/de/rwth/idsg/steve/ocpp/ws/JsonObjectMapper.java
@@ -20,7 +20,6 @@
 
 import com.fasterxml.jackson.annotation.JsonInclude;
 import de.rwth.idsg.ocpp.jaxb.validation.BeanValidationModule;
-import de.rwth.idsg.steve.ocpp.ws.custom.CustomStringModule;
 import de.rwth.idsg.steve.ocpp.ws.ocpp12.Ocpp12JacksonModule;
 import de.rwth.idsg.steve.ocpp.ws.ocpp15.Ocpp15JacksonModule;
 import de.rwth.idsg.steve.ocpp.ws.ocpp16.Ocpp16JacksonModule;
@@ -59,7 +58,6 @@ public enum JsonObjectMapper {
             .enable(FAIL_ON_NULL_FOR_PRIMITIVES)
             .enable(WRITE_BIGDECIMAL_AS_PLAIN)
             .disable(FAIL_ON_UNKNOWN_PROPERTIES)
-            .addModule(new CustomStringModule())
             .addModule(new Ocpp12JacksonModule())
             .addModule(new Ocpp15JacksonModule())
             .addModule(new Ocpp16JacksonModule())
diff --git a/src/main/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModule.java b/src/main/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModule.java
deleted file mode 100644
index 61ab38de3..000000000
--- a/src/main/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModule.java
+++ /dev/null
@@ -1,94 +0,0 @@
-/*
- * SteVe - SteckdosenVerwaltung - https://github.com/steve-community/steve
- * Copyright (C) 2013-2026 SteVe Community Team
- * All Rights Reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-package de.rwth.idsg.steve.ocpp.ws.custom;
-
-import org.owasp.encoder.Encode;
-import tools.jackson.core.JacksonException;
-import tools.jackson.core.JsonGenerator;
-import tools.jackson.core.JsonParser;
-import tools.jackson.core.Version;
-import tools.jackson.databind.DatabindException;
-import tools.jackson.databind.DeserializationContext;
-import tools.jackson.databind.JavaType;
-import tools.jackson.databind.SerializationContext;
-import tools.jackson.databind.deser.jdk.StringDeserializer;
-import tools.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
-import tools.jackson.databind.jsontype.TypeSerializer;
-import tools.jackson.databind.module.SimpleModule;
-import tools.jackson.databind.ser.jdk.StringSerializer;
-import tools.jackson.databind.ser.std.StdScalarSerializer;
-
-/**
- * @author Sevket Goekay <sevketgokay@gmail.com>
- * @since 17.08.2022
- */
-public class CustomStringModule extends SimpleModule {
-
-    public CustomStringModule() {
-        super("CustomStringModule", new Version(0, 0, 1, null, "de.rwth.idsg", "steve"));
-
-        super.addSerializer(String.class, new CustomStringSerializer());
-        super.addDeserializer(String.class, new CustomStringDeserializer());
-    }
-
-    /**
-     * Since {@link StringSerializer} is marked as final, its contents are copied here (and adjusted as needed).
-     */
-    private static class CustomStringSerializer extends StdScalarSerializer<Object> {
-
-        public CustomStringSerializer() {
-            super(String.class, false);
-        }
-
-        @Override
-        public boolean isEmpty(SerializationContext prov, Object value) {
-            String str = (String) value;
-            return str.isEmpty();
-        }
-
-        @Override
-        public void serialize(Object value, JsonGenerator gen, SerializationContext provider) throws JacksonException {
-            gen.writeString(objectToString(value));
-        }
-
-        @Override
-        public final void serializeWithType(Object value, JsonGenerator gen, SerializationContext provider,
-                                            TypeSerializer typeSer) throws JacksonException {
-            gen.writeString(objectToString(value));
-        }
-
-        @Override
-        public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws DatabindException {
-            visitStringFormat(visitor, typeHint);
-        }
-
-        private static String objectToString(Object value) {
-            return Encode.forHtml((String) value);
-        }
-    }
-
-    private static class CustomStringDeserializer extends StringDeserializer {
-
-        @Override
-        public String deserialize(JsonParser p, DeserializationContext ctxt) throws JacksonException {
-            String val = super.deserialize(p, ctxt);
-            return Encode.forHtml(val);
-        }
-    }
-}
diff --git a/src/test/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModuleTest.java b/src/test/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModuleTest.java
index 7cbb9ce46..671b75c98 100644
--- a/src/test/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModuleTest.java
+++ b/src/test/java/de/rwth/idsg/steve/ocpp/ws/custom/CustomStringModuleTest.java
@@ -25,6 +25,10 @@
 import org.junit.jupiter.api.Test;
 
 /**
+ * Verifies that the Jackson ObjectMapper does not HTML-encode string values.
+ * Strings must be serialized using standard JSON escaping (RFC 8259) so that
+ * OCPP wire payloads are not corrupted.
+ *
  * @author Sevket Goekay <sevketgokay@gmail.com>
  * @since 17.08.2022
  */
@@ -43,14 +47,40 @@ public void testNormalString() throws Exception {
     public void testLink() throws Exception {
         SimpleJsonModel input = new SimpleJsonModel("<a href=\"link\">Some link</a>");
         String output = mapper.writeValueAsString(input);
-        Assertions.assertEquals("{\"someText\":\"&lt;a href=&#34;link&#34;&gt;Some link&lt;/a&gt;\"}", output);
+        // Standard JSON escaping: quotes inside strings are escaped with backslash,
+        // angle brackets are passed through unmodified (no HTML encoding).
+        Assertions.assertEquals("{\"someText\":\"<a href=\\\"link\\\">Some link</a>\"}", output);
     }
 
     @Test
     public void testScript() throws Exception {
         SimpleJsonModel input = new SimpleJsonModel("<script src=\"http://someurl.com/script.js\"/>");
         String output = mapper.writeValueAsString(input);
-        Assertions.assertEquals("{\"someText\":\"&lt;script src=&#34;http://someurl.com/script.js&#34;/&gt;\"}", output);
+        // Standard JSON escaping: no HTML encoding of angle brackets or quotes.
+        Assertions.assertEquals("{\"someText\":\"<script src=\\\"http://someurl.com/script.js\\\"/>\"}", output);
+    }
+
+    @Test
+    public void testDataTransferWithQuotes() throws Exception {
+        // Reproduces the bug from issue #938: DataTransfer payloads with embedded quotes
+        // must not be HTML-encoded.
+        String data = "{\"txId\":\"123456\",\"description\": \"Charging:$2.81\"}";
+        SimpleJsonModel input = new SimpleJsonModel(data);
+        String output = mapper.writeValueAsString(input);
+        Assertions.assertEquals(
+            "{\"someText\":\"{\\\"txId\\\":\\\"123456\\\",\\\"description\\\": \\\"Charging:$2.81\\\"}\"}",
+            output
+        );
+    }
+
+    @Test
+    public void testRoundTrip() throws Exception {
+        // Verify that serialization followed by deserialization preserves the original string.
+        String original = "<script>alert(\"xss\")</script>";
+        SimpleJsonModel input = new SimpleJsonModel(original);
+        String json = mapper.writeValueAsString(input);
+        SimpleJsonModel deserialized = mapper.readValue(json, SimpleJsonModel.class);
+        Assertions.assertEquals(original, deserialized.getSomeText());
     }
 
     @Data