diff --git a/backend-diagram-converter/core/src/main/java/org/camunda/community/migration/converter/expression/ExpressionTransformer.java b/backend-diagram-converter/core/src/main/java/org/camunda/community/migration/converter/expression/ExpressionTransformer.java
index eada45bf4..b62021e3f 100644
--- a/backend-diagram-converter/core/src/main/java/org/camunda/community/migration/converter/expression/ExpressionTransformer.java
+++ b/backend-diagram-converter/core/src/main/java/org/camunda/community/migration/converter/expression/ExpressionTransformer.java
@@ -67,7 +67,8 @@ private String handleExpression(String expression) {
             // replace all !(x and y) with not(x and y)
             .replaceAll("!\\(([^\\(\\)]*)\\)", "not($1)")
             .replaceAll(" && ", " and ")
-            .replaceAll(" \\|\\| ", " or ");
+            .replaceAll(" \\|\\| ", " or ")
+            .replaceAll("'", "\"");
     // increment all indexes
     Pattern pattern = Pattern.compile("\\[(\\d*)\\]");
     Matcher m = pattern.matcher(replaced);
diff --git a/backend-diagram-converter/core/src/test/java/org/camunda/community/migration/converter/ExpressionTransformerTest.java b/backend-diagram-converter/core/src/test/java/org/camunda/community/migration/converter/ExpressionTransformerTest.java
index d26c3f4bc..dc744c4ab 100644
--- a/backend-diagram-converter/core/src/test/java/org/camunda/community/migration/converter/ExpressionTransformerTest.java
+++ b/backend-diagram-converter/core/src/test/java/org/camunda/community/migration/converter/ExpressionTransformerTest.java
@@ -63,7 +63,9 @@ public Stream<DynamicContainer> shouldResolveExpression() {
             expression("${!dauerbuchungVoat21Ids.isEmpty()}").hasMethodInvocation(true),
             expression("${!dauerbuchungVoat21Ids.contains(\"someText\")}")
                 .hasMethodInvocation(true),
-            expression("${input > 5.5}").hasMethodInvocation(false))
+            expression("${input > 5.5}").hasMethodInvocation(false),
+            expression("${input != ''}").isMappedTo("=input != \"\""),
+            expression("${input != 'what the F***'}").isMappedTo("=input != \"what the F***\""))
         .map(
             data ->
                 DynamicContainer.dynamicContainer(