diff --git a/acstools/acs_destripe.py b/acstools/acs_destripe.py
index 6faab817..1af54c9e 100644
--- a/acstools/acs_destripe.py
+++ b/acstools/acs_destripe.py
@@ -549,9 +549,17 @@ def perform_correction(image, output, stat="pmode1", maxiter=15, sigrej=2.0,
 
 
 def _mergeUserMaskAndDQ(dq, mask, dqbits):
-    from stsci.tools import bitmask  # Optional package dependency
+    # Optional package dependency
+    try:
+        from stsci.tools.bitmask import (interpret_bit_flags,
+                                         bitfield_to_boolean_mask)
+    except ImportError:
+        from stsci.tools.bitmask import (
+            interpret_bits_value as interpret_bit_flags,
+            bitmask2mask as bitfield_to_boolean_mask
+        )
 
-    dqbits = bitmask.interpret_bits_value(dqbits)
+    dqbits = interpret_bit_flags(dqbits)
     if dqbits is None:
         if mask is None:
             return None
@@ -561,8 +569,9 @@ def _mergeUserMaskAndDQ(dq, mask, dqbits):
     if dq is None:
         raise ValueError("DQ array is None while 'dqbits' is not None.")
 
-    dqmask = bitmask.bitmask2mask(bitmask=dq, ignore_bits=dqbits,
-                                  good_mask_value=1, dtype=np.uint8)
+    dqmask = bitfield_to_boolean_mask(dq, ignore_bits=dqbits,
+                                      good_mask_value=1, dtype=np.uint8)
+
     if mask is None:
         return dqmask
 
diff --git a/acstools/acs_destripe_plus.py b/acstools/acs_destripe_plus.py
index 9225e978..9ca598d7 100644
--- a/acstools/acs_destripe_plus.py
+++ b/acstools/acs_destripe_plus.py
@@ -272,7 +272,12 @@ def destripe_plus(inputfile, suffix='strp', stat='pmode1', maxiter=15,
     """
     # Optional package dependencies
     from stsci.tools import parseinput
-    from stsci.tools import bitmask
+    try:
+        from stsci.tools.bitmask import interpret_bit_flags
+    except ImportError:
+        from stsci.tools.bitmask import (
+            interpret_bits_value as interpret_bit_flags
+        )
 
     # process input file(s) and if we have multiple input files - recursively
     # call acs_destripe_plus for each input image:
@@ -416,7 +421,7 @@ def destripe_plus(inputfile, suffix='strp', stat='pmode1', maxiter=15,
     acsccd.acsccd(inputfile)
 
     # modify user mask with DQ masks if requested
-    dqbits = bitmask.interpret_bits_value(dqbits)
+    dqbits = interpret_bit_flags(dqbits)
     if dqbits is not None:
         # save 'tra' file in memory to trick the log file
         # not to save first acs2d log as this is done only