diff --git a/requirements.txt b/requirements.txt
index 08a17b7..36ed34a 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,7 @@ gensim>=3.4.0,<4.0
 jupyter>=1.0.0,<3.0.0  # pandas>=0.23.4,<0.30.0
 matplotlib>=2.2.3,<2.3.0
 nltk>=3.2.5,<3.5.0
-nlup==0.5
+# nlup==0.5
 pandas>=0.24.2,<0.25.0
 pip>=18.0
 plotly>=3.2.1,<3.4.0
diff --git a/setup.cfg b/setup.cfg
index bcce2d1..ce1a929 100755
--- a/setup.cfg
+++ b/setup.cfg
@@ -38,7 +38,7 @@ include_package_data = True
 package_dir =
     =src
 # Add here dependencies of your project (semicolon-separated), e.g.
-install_requires = coverage; future; fuzzywuzzy; jupyter; matplotlib; nltk; nlup==0.5; pandas; pip; pypandoc; python-Levenshtein; python-slugify; scikit-learn; scipy; plotly; seaborn; tqdm; wheel; gensim;
+install_requires = coverage; future; fuzzywuzzy; jupyter; matplotlib; nltk; pandas; pip; pypandoc; python-Levenshtein; python-slugify; scikit-learn; scipy; plotly; seaborn; tqdm; wheel; gensim;
 # Add here test requirements (semicolon-separated)
 tests_require = pytest; pytest-cov
 
diff --git a/src/pugnlp/detector_morse.py b/src/pugnlp/detector_morse.py
index 992dc5a..19dbf0a 100755
--- a/src/pugnlp/detector_morse.py
+++ b/src/pugnlp/detector_morse.py
@@ -31,14 +31,17 @@
 from future import standard_library
 standard_library.install_aliases()  # noqa
 
+from collections import namedtuple
 import logging
 from re import finditer, match, search
-from collections import namedtuple
-
-from nlup import case_feature, isnumberlike, listify, BinaryAveragedPerceptron, BinaryConfusion, IO, JSONable
 
 from .penn_treebank_tokenizer import word_tokenize
+
 logger = logging.getLogger(__name__)
+try:
+    from nlup import case_feature, isnumberlike, listify, BinaryAveragedPerceptron, BinaryConfusion, IO, JSONable
+except ImportError:
+    logger.error("detector_morse disabled because Kyle Gorman's nlup sentence boundary detector has not been installed.")
 # FIXME(kbg) can surely avoid full-blown tokenization
 
 
diff --git a/src/pugnlp/segmentation.py b/src/pugnlp/segmentation.py
index 674d444..8f52b99 100755
--- a/src/pugnlp/segmentation.py
+++ b/src/pugnlp/segmentation.py
@@ -12,20 +12,25 @@
 import os
 import re
 from itertools import chain
+import logging
 
-import nltk.stem
-
-from pugnlp.detector_morse import Detector
-from pugnlp.detector_morse import slurp
-from pugnlp.futil import find_files
-# from .penn_treebank_tokenizer import word_tokenize
-import nlup
 
+import nltk.stem
+from .detector_morse import Detector
+from .detector_morse import slurp
+from .futil import find_files
 from .constants import DATA_PATH
 from .futil import generate_files
 from .util import stringify, passthrough
+from .regexes import CRE_TOKEN, RE_NONWORD
+
+# from .penn_treebank_tokenizer import word_tokenize
 
-from pugnlp.regexes import CRE_TOKEN, RE_NONWORD
+logger = logging.getLogger(__name__)
+try:
+    import nlup
+except ImportError:
+    logger.error("detector_morse disabled because Kyle Gorman's nlup sentence boundary detector has not been installed.")
 
 
 class Split(object):