diff --git a/CHANGES.txt b/CHANGES.txt
index 5e62c1c..d50310c 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,6 @@
+Jan 28, 2014 - v0.5.10  Fixed bad warning when reader requirements box mask
+    length is unsupported.
+
 Oct 29, 2013 - v0.5.9  Fixed bad library load on linux as a result of 0.5.8
 
 Oct 29, 2013 - v0.5.8  Fixed unnecessary warnings when default locations for
diff --git a/docs/source/conf.py b/docs/source/conf.py
index b14af27..4b0eb14 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -78,7 +78,7 @@ copyright = u'2013, John Evans'
 # The short X.Y version.
 version = '0.5'
 # The full version, including alpha/beta/rc tags.
-release = '0.5.9'
+release = '0.5.10'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/docs/source/roadmap.rst b/docs/source/roadmap.rst
index f9216a3..1e336f1 100644
--- a/docs/source/roadmap.rst
+++ b/docs/source/roadmap.rst
@@ -9,3 +9,4 @@ Here's an incomplete list of what I'd like to focus on in the future.
     * investigate adding write support for UUID/XMP boxes (potentially a big project)
     * investigate JPIP (likely to be an even bigger project)
     
+Support for Python 2.6 will be dropped with the 0.6.0 release.
diff --git a/glymur/jp2box.py b/glymur/jp2box.py
index bf88e4d..2b40630 100644
--- a/glymur/jp2box.py
+++ b/glymur/jp2box.py
@@ -1465,13 +1465,24 @@ class ReaderRequirementsBox(Jp2kBox):
         # Decodes Completely Mask
         read_buffer = fptr.read(2 * mask_length)
 
+        fuam = dcm = standard_flag = standard_mask = []
+        vendor_feature = vendor_mask = []
+
         # The mask length tells us the format string to use when unpacking
         # from the buffer read from file.
-        mask_format = {1: 'B', 2: 'H', 4: 'I'}[mask_length]
-        fuam, dcm = struct.unpack('>' + mask_format * 2, read_buffer)
+        try:
+            mask_format = {1: 'B', 2: 'H', 4: 'I', 8: 'Q'}[mask_length]
+            fuam, dcm = struct.unpack('>' + mask_format * 2, read_buffer)
+            standard_flag, standard_mask = _parse_standard_flag(fptr,
+                                                                mask_length)
+            vendor_feature, vendor_mask = _parse_vendor_features(fptr,
+                                                                 mask_length)
 
-        standard_flag, standard_mask = _parse_standard_flag(fptr, mask_length)
-        vendor_feature, vendor_mask = _parse_vendor_features(fptr, mask_length)
+        except KeyError:
+            msg = 'The ReaderRequirements box (rreq) has a mask length of {0} '
+            msg += 'bytes, but only values of 1, 2, 4, or 8 are supported.  '
+            msg += 'The box contents will not be interpreted.'
+            warnings.warn(msg.format(mask_length), UserWarning)
 
         box = ReaderRequirementsBox(fuam, dcm, standard_flag, standard_mask,
                                     vendor_feature, vendor_mask,
diff --git a/glymur/test/test_jp2box_jpx.py b/glymur/test/test_jp2box_jpx.py
new file mode 100644
index 0000000..344a3cd
--- /dev/null
+++ b/glymur/test/test_jp2box_jpx.py
@@ -0,0 +1,61 @@
+# -*- coding:  utf-8 -*-
+"""
+Test suite specifically targeting JPX box layout.
+"""
+
+import os
+import struct
+import sys
+import tempfile
+import warnings
+import xml.etree.cElementTree as ET
+
+if sys.hexversion < 0x02070000:
+    import unittest2 as unittest
+else:
+    import unittest
+
+import glymur
+from glymur import Jp2k
+from glymur.jp2box import ReaderRequirementsBox
+
+
+@unittest.skipIf(sys.hexversion < 0x03000000, "Warning assert on 2.x.")
+@unittest.skipIf(os.name == "nt", "Temporary file issue on window.")
+class TestReaderRequirements(unittest.TestCase):
+    """Test suite for XML boxes."""
+
+    def setUp(self):
+        self.jp2file = glymur.data.nemo()
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_mask_length_is_3(self):
+        """The standard says that the mask length should be 1, 2, 4, or 8."""
+        # Rewrite nemo to include this kind of rreq box.
+        with tempfile.NamedTemporaryFile(suffix=".jpx") as tfile:
+            with open(self.jp2file, 'rb') as nemof:
+                # Read the jP and ftyp boxes as-is.
+                write_buffer = nemof.read(32)
+                tfile.write(write_buffer)
+
+                # Fake a rreq box with ML = 3.
+                write_buffer = struct.pack('>I4sB', 74, b'rreq', 3)
+                tfile.write(write_buffer)
+
+                # pad the rest with zeros 
+                write_buffer = struct.pack('>65s', b'\x00' * 65)
+                tfile.write(write_buffer)
+
+                # Write the rest of nemo.
+                tfile.write(nemof.read())
+                tfile.flush()
+
+            with self.assertWarns(UserWarning):
+                j = Jp2k(tfile.name)
+            self.assertEqual(j.box[2].box_id, 'rreq')
+            self.assertEqual(type(j.box[2]),
+                             glymur.jp2box.ReaderRequirementsBox)
+
diff --git a/glymur/version.py b/glymur/version.py
index 6116920..d3d87db 100644
--- a/glymur/version.py
+++ b/glymur/version.py
@@ -15,7 +15,7 @@ from .lib import openjp2 as opj2
 
 # Do not change the format of this next line!  Doing so risks breaking
 # setup.py
-version = "0.5.9"
+version = "0.5.10"
 _sv = LooseVersion(version)
 version_tuple = _sv.version
 
diff --git a/setup.py b/setup.py
index 89e69f7..e2f72f0 100644
--- a/setup.py
+++ b/setup.py
@@ -7,7 +7,7 @@ kwargs = {'name': 'Glymur',
           'description': 'Tools for accessing JPEG2000 files',
           'long_description': open('README.md').read(),
           'author': 'John Evans',
-          'author_email': 'john.g.evans.ne at gmail dot com',
+          'author_email': 'john.g.evans.ne@gmail.com',
           'url': 'https://github.com/quintusdias/glymur',
           'packages': ['glymur', 'glymur.data', 'glymur.test', 'glymur.lib',
                        'glymur.lib.test'],