diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 6ac62c5dc..b6567fb01 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 4.2.0
+current_version = 4.2.1
 commit = True
 
 [bumpversion:file:ibm_watson/version.py]
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 292541a5f..05e771fee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## [4.2.1](https://github.com/watson-developer-cloud/python-sdk/compare/v4.2.0...v4.2.1) (2020-01-17)
+
+
+### Bug Fixes
+
+* **nlu:** Add model property back in CategoriesOptions ([6d5ed34](https://github.com/watson-developer-cloud/python-sdk/commit/6d5ed3404408a32daa90490daa9be24f53512998))
+
 # [4.2.0](https://github.com/watson-developer-cloud/python-sdk/compare/v4.1.0...v4.2.0) (2020-01-16)
 
 
diff --git a/ibm_watson/natural_language_understanding_v1.py b/ibm_watson/natural_language_understanding_v1.py
index 60948e696..abe046a73 100644
--- a/ibm_watson/natural_language_understanding_v1.py
+++ b/ibm_watson/natural_language_understanding_v1.py
@@ -716,9 +716,15 @@ class CategoriesOptions():
     :attr bool explanation: (optional) Set this to `true` to return explanations for
           each categorization. **This is available only for English categories.**.
     :attr int limit: (optional) Maximum number of categories to return.
+    :attr str model: (optional) Deprecated: Enter a [custom model]
+          (https://cloud.ibm.com/docs/services/natural-language-understanding?topic=natural-language-understanding-customizing)
+          ID to override the standard categories model. The custom categories experimental feature will be retired on
+          19 December 2019. On that date, deployed custom categories models will no longer be accessible in Natural Language
+          Understanding. The feature will be removed from Knowledge Studio on an earlier date. Custom categories models will
+          no longer be accessible in Knowledge Studio on 17 December 2019.
     """
 
-    def __init__(self, *, explanation: bool = None, limit: int = None) -> None:
+    def __init__(self, *, explanation: bool = None, limit: int = None, model: str = None) -> None:
         """
         Initialize a CategoriesOptions object.
 
@@ -726,6 +732,12 @@ def __init__(self, *, explanation: bool = None, limit: int = None) -> None:
                explanations for each categorization. **This is available only for English
                categories.**.
         :param int limit: (optional) Maximum number of categories to return.
+        :attr str model: (optional) Deprecated: Enter a [custom model]
+               (https://cloud.ibm.com/docs/services/natural-language-understanding?topic=natural-language-understanding-customizing)
+               ID to override the standard categories model. The custom categories experimental feature will be retired on
+               19 December 2019. On that date, deployed custom categories models will no longer be accessible in Natural Language
+               Understanding. The feature will be removed from Knowledge Studio on an earlier date. Custom categories models will
+               no longer be accessible in Knowledge Studio on 17 December 2019.
         """
         self.explanation = explanation
         self.limit = limit
diff --git a/ibm_watson/version.py b/ibm_watson/version.py
index ea5d65fc7..0d6a4f2bf 100644
--- a/ibm_watson/version.py
+++ b/ibm_watson/version.py
@@ -1 +1 @@
-__version__ = '4.2.0'
+__version__ = '4.2.1'
diff --git a/package-lock.json b/package-lock.json
index 6dfeb67ad..845b68c01 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -193,9 +193,9 @@
       "integrity": "sha512-tHq6qdbT9U1IRSGf14CL0pUlULksvY9OZ+5eEgl1N7t+OA3tGvNpxJCzuKQlsNgCVwbAs670L1vcVQi8j9HjnA=="
     },
     "@types/node": {
-      "version": "13.1.7",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-13.1.7.tgz",
-      "integrity": "sha512-HU0q9GXazqiKwviVxg9SI/+t/nAsGkvLDkIdxz+ObejG2nX6Si00TeLqHMoS+a/1tjH7a8YpKVQwtgHuMQsldg=="
+      "version": "13.1.8",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-13.1.8.tgz",
+      "integrity": "sha512-6XzyyNM9EKQW4HKuzbo/CkOIjn/evtCmsU+MUM1xDfJ+3/rNjBttM1NgN7AOQvN6tP1Sl1D1PIKMreTArnxM9A=="
     },
     "@types/retry": {
       "version": "0.12.0",
diff --git a/setup.py b/setup.py
index 91f4987c3..0ea62d9c5 100644
--- a/setup.py
+++ b/setup.py
@@ -18,7 +18,7 @@
 import os
 import sys
 
-__version__ = '4.2.0'
+__version__ = '4.2.1'
 
 
 if sys.argv[-1] == 'publish':