diff --git a/dls_barcode/datamatrix/datamatrix.py b/dls_barcode/datamatrix/datamatrix.py
index 5c24764..9dd5e60 100644
--- a/dls_barcode/datamatrix/datamatrix.py
+++ b/dls_barcode/datamatrix/datamatrix.py
@@ -1,9 +1,12 @@
 import logging
-from dls_util.image.image import Image
-from .locate import Locator
+import string
+from string import ascii_lowercase
+
 from pylibdmtx.pylibdmtx import decode
-import cv2
 
+from dls_util.image.image import Image
+
+from .locate import Locator
 
 # We predict the location of the center of each square (pixel/bit) in the datamatrix based on the
 # size and location of the finder pattern, but this can sometimes be slightly off. If the initial
@@ -25,6 +28,8 @@ class DataMatrix:
     """
     DEFAULT_SIZE = 14
     DEFAULT_SIDE_SIZES = [12, 14]
+    # allow only capitol letters, digits and dash in the decoded string
+    ALLOWED_CHARS = set(string.ascii_uppercase + string.ascii_lowercase + string.digits + '-' + '_')
 
     def __init__(self, finder_pattern):
         """ Initialize the DataMatrix object with its finder pattern location in an image. To actually
@@ -107,16 +112,17 @@ def _read(self, gray_image):
         given by the datamatrix finder pattern.
         """
         try:
-            
-
             result = decode(gray_image, max_count = 1)
             if len(result) > 0:
                 d = result[0].data
                 decoded = d.decode('UTF-8')
-                new_line_removed = decoded.replace("\n","")
-                self._data = new_line_removed
-                self._read_ok = True
-                self._error_message = ""
+                if self._contains_allowed_chars_only(decoded):
+                    new_line_removed = decoded.replace("\n","")
+                    self._data = new_line_removed
+                    self._read_ok = True
+                    self._error_message = ""
+                else:
+                    self._read_ok = False
             else:
                 self._read_ok = False
                 #cv2.imshow("Erode", gray_image)
@@ -133,6 +139,9 @@ def draw(self, img, color):
         img.draw_line(fp.c1, fp.c2, color)
         img.draw_line(fp.c1, fp.c3, color)
 
+    def _contains_allowed_chars_only(self, text):
+        return (set(text)).issubset(self.ALLOWED_CHARS)
+
     @staticmethod
     def locate_all_barcodes_in_image(grayscale_img, matrix_sizes=[DEFAULT_SIZE]):
         """ Searches the image for all datamatrix finder patterns
diff --git a/dls_barcode/version.py b/dls_barcode/version.py
index 3d3e3ea..ad6fb3a 100644
--- a/dls_barcode/version.py
+++ b/dls_barcode/version.py
@@ -1 +1 @@
-VERSION = "v1.8.0"
\ No newline at end of file
+VERSION = "v1.9.0"
\ No newline at end of file
diff --git a/docs/release-notes/release-notes-dev.md b/docs/release-notes/release-notes-dev.md
index 35cad06..af0594e 100644
--- a/docs/release-notes/release-notes-dev.md
+++ b/docs/release-notes/release-notes-dev.md
@@ -5,8 +5,8 @@ Changes merged into master
 --------------------------
 | Jira Task | GitHub Issue | Type | Description                        |
 |-----------|--------------|------|------------------------------------|
-|     -     |     -        |      |Use python 3.7                      |
-|I04_1-1036 |     -        |Minor |Use pylibdtmx to read barcodes      | 
+|     -     |     -        |      |                                    |
+|     -     |     -        |      |                                    | 
 
 Change Types:
 * Major - Backward incompatible change
diff --git a/docs/release-notes/release-notes-v1_9_0.md b/docs/release-notes/release-notes-v1_9_0.md
new file mode 100644
index 0000000..88742d5
--- /dev/null
+++ b/docs/release-notes/release-notes-v1_9_0.md
@@ -0,0 +1,16 @@
+Release Notes (Development)
+===========================
+
+Changes merged into master
+--------------------------
+| Jira Task | GitHub Issue | Type | Description                           |
+|-----------|--------------|------|---------------------------------------|
+|I04_1-1062 |     -        |Minor |Only letters, numbers, _ and -  allowed| 
+
+Change Types:
+* Major - Backward incompatible change
+* Minor - Backward compatible change in API/functionality
+* Patch - Bug fix, no change in functionality
+
+
+
diff --git a/tests/unit_tests/test_dls_barcode/test_datamatrix/test_datamatrix.py b/tests/unit_tests/test_dls_barcode/test_datamatrix/test_datamatrix.py
new file mode 100644
index 0000000..6296bb9
--- /dev/null
+++ b/tests/unit_tests/test_dls_barcode/test_datamatrix/test_datamatrix.py
@@ -0,0 +1,19 @@
+import unittest
+
+from mock import Mock, patch
+
+from dls_barcode.datamatrix.datamatrix import DataMatrix
+
+class TestDatamatrix(unittest.TestCase):
+
+    def test_contains_allowed_characers(self):
+        datamatrix = DataMatrix(Mock)
+        test_string_good = "AbcD123_-"
+        self.assertTrue(datamatrix._contains_allowed_chars_only(test_string_good))
+
+        test_string_bad = "AbcD123_-$<"
+        self.assertFalse(datamatrix._contains_allowed_chars_only(test_string_bad))
+
+
+            
+