diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0dd99aa..d52d7e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Upgraded `statsmodels` to `0.14.0`.
+- Upgraded `dataclasses-json` to `0.5.8`.
 
 ## [v0.13.1] - 2023-03-07
 ### Changed
diff --git a/algorithms/holt_winters/holt_winters.py b/algorithms/holt_winters/holt_winters.py
index 1eeb7d7..e462dee 100644
--- a/algorithms/holt_winters/holt_winters.py
+++ b/algorithms/holt_winters/holt_winters.py
@@ -105,7 +105,8 @@ class AlgorithmInput:
 
 fitted_model = model.fit(smoothing_level=algorithm_input.alpha,
                          smoothing_trend=algorithm_input.beta,
-                         smoothing_seasonal=algorithm_input.gamma)
+                         smoothing_seasonal=algorithm_input.gamma,
+                         optimized=False)
 
 # Predict the value one ahead
 print(math.ceil(fitted_model.forecast(steps=1)[0]), end="")
diff --git a/algorithms/holt_winters/test_holt_winters.py b/algorithms/holt_winters/test_holt_winters.py
index 4f66fb5..9cd50d6 100644
--- a/algorithms/holt_winters/test_holt_winters.py
+++ b/algorithms/holt_winters/test_holt_winters.py
@@ -124,7 +124,7 @@ def test_holt_winters(subtests):
         "expected_stderr":
         "",
         "expected_stdout":
-        "7",
+        "6",
         "stdin":
         """{
                 "trend": "add",
diff --git a/algorithms/requirements.txt b/algorithms/requirements.txt
index 44e43c6..48b0942 100644
--- a/algorithms/requirements.txt
+++ b/algorithms/requirements.txt
@@ -1,2 +1,2 @@
-statsmodels==0.13.2
-dataclasses-json==0.5.7
+statsmodels==0.14.0
+dataclasses-json==0.5.8
diff --git a/examples/dynamic-holt-winters/tuning/requirements.txt b/examples/dynamic-holt-winters/tuning/requirements.txt
index c9edc1a..5aad892 100644
--- a/examples/dynamic-holt-winters/tuning/requirements.txt
+++ b/examples/dynamic-holt-winters/tuning/requirements.txt
@@ -1 +1 @@
-Flask==2.2.2
+Flask==2.3.2