diff --git a/CHANGES.rst b/CHANGES.rst
index 1facf5c7f..1053b20ac 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -6,6 +6,16 @@ APT Pointing File
 
 Bug fix such that the only Target Acquisition observations that are read in are those for NIRCam TSO observations.
 
+Header Keywords
+---------------
+
+Corrected schema to populate the XOFFSET and YOFFSET header keywords (#454)
+
+Reference Files
+---------------
+
+Fix bug in downloader that was preventing NIRISS darks from being downloaded (#450)
+
 
 1.3.2
 =====
diff --git a/mirage/ramp_generator/obs_generator.py b/mirage/ramp_generator/obs_generator.py
index 77b209726..00f58030b 100755
--- a/mirage/ramp_generator/obs_generator.py
+++ b/mirage/ramp_generator/obs_generator.py
@@ -2874,8 +2874,8 @@ def save_DMS(self, ramp, zeroframe, filename, mod='1b', err_ext=None,
         outModel.meta.dither.subpixel_type = self.params['Output']['subpix_dither_type']
         outModel.meta.dither.subpixel_number = self.params['Output']['subpix_dither_position']
         outModel.meta.dither.subpixel_total_points = self.params['Output']['total_subpix_dither_positions']
-        outModel.meta.dither.xoffset = self.params['Output']['xoffset']
-        outModel.meta.dither.yoffset = self.params['Output']['yoffset']
+        outModel.meta.dither.x_offset = self.params['Output']['xoffset']
+        outModel.meta.dither.y_offset = self.params['Output']['yoffset']
 
         # pixel coordinates in FITS header start from 1 not from 0
         xc = (self.subarray_bounds[2] + self.subarray_bounds[0])/2.+1.
diff --git a/mirage/reference_files/downloader.py b/mirage/reference_files/downloader.py
index f4b65d9fe..79ee1968c 100644
--- a/mirage/reference_files/downloader.py
+++ b/mirage/reference_files/downloader.py
@@ -314,7 +314,7 @@ def download_reffiles(directory, instrument='all', dark_type='linearized',
                     det_str.replace('LONG', '5')
                 darks_dir = os.path.join(directory, 'mirage_data', 'nircam', 'darks')
                 sub_directory = os.path.join(darks_dir, cal, det_str)
-            elif 'NIRISS' in filename.lower():
+            elif 'NIRISS' in filename:
                 darks_dir = os.path.join(directory, 'mirage_data', 'niriss', 'darks')
                 sub_directory = os.path.join(darks_dir, cal)
                 #sub_directory = os.path.join(directory, 'mirage_data', 'niriss', 'darks', cal)