helloflask · greyli · Aug 23, 2026 · Aug 23, 2026
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -4,6 +4,7 @@ Changelog
 - Upgrade to Bootstrap Icons 1.13.1.
 - Drop Python 3.9 and 3.10 support.
 - Upgrade to Bootstrap 5.3.8
+- Upgrade Bootstrap 4 and Bootswatch to 4.6.2.
 
 2.5.0
 -----

diff --git a/examples/bootstrap4/app.py b/examples/bootstrap4/app.py
@@ -102,27 +102,27 @@ class BootswatchForm(FlaskForm):
         default='default',
         choices=[
             ('default', 'none'),
-            ('cerulean', 'Cerulean 4.6.1'),
-            ('cosmo', 'Cosmo 4.6.1'),
-            ('cyborg', 'Cyborg 4.6.1'),
-            ('darkly', 'Darkly 4.6.1'),
-            ('flatly', 'Flatly 4.6.1'),
-            ('journal', 'Journal 4.6.1'),
-            ('litera', 'Litera 4.6.1'),
-            ('lumen', 'Lumen 4.6.1'),
-            ('lux', 'Lux 4.6.1'),
-            ('materia', 'Materia 4.6.1'),
-            ('minty', 'Minty 4.6.1'),
-            ('pulse', 'Pulse 4.6.1'),
-            ('sandstone', 'Sandstone 4.6.1'),
-            ('simplex', 'Simplex 4.6.1'),
-            ('sketchy', 'Sketchy 4.6.1'),
-            ('slate', 'Slate 4.6.1'),
-            ('solar', 'Solar 4.6.1'),
-            ('spacelab', 'Spacelab 4.6.1'),
-            ('superhero', 'Superhero 4.6.1'),
-            ('united', 'United 4.6.1'),
-            ('yeti', 'Yeti 4.6.1'),
+            ('cerulean', 'Cerulean 4.6.2'),
+            ('cosmo', 'Cosmo 4.6.2'),
+            ('cyborg', 'Cyborg 4.6.2'),
+            ('darkly', 'Darkly 4.6.2'),
+            ('flatly', 'Flatly 4.6.2'),
+            ('journal', 'Journal 4.6.2'),
+            ('litera', 'Litera 4.6.2'),
+            ('lumen', 'Lumen 4.6.2'),
+            ('lux', 'Lux 4.6.2'),
+            ('materia', 'Materia 4.6.2'),
+            ('minty', 'Minty 4.6.2'),
+            ('pulse', 'Pulse 4.6.2'),
+            ('sandstone', 'Sandstone 4.6.2'),
+            ('simplex', 'Simplex 4.6.2'),
+            ('sketchy', 'Sketchy 4.6.2'),
+            ('slate', 'Slate 4.6.2'),
+            ('solar', 'Solar 4.6.2'),
+            ('spacelab', 'Spacelab 4.6.2'),
+            ('superhero', 'Superhero 4.6.2'),
+            ('united', 'United 4.6.2'),
+            ('yeti', 'Yeti 4.6.2'),
         ]
     )
     submit = SubmitField()

diff --git a/flask_bootstrap/__init__.py b/flask_bootstrap/__init__.py
@@ -240,12 +240,12 @@ def create_app():
        Move common logic to base class ``_Bootstrap``.
     """
 
-    bootstrap_version = '4.6.1'
+    bootstrap_version = '4.6.2'
     jquery_version = '3.5.1'
     popper_version = '1.16.1'
     icons_version = '1.13.1'
-    bootstrap_css_integrity = 'sha384-zCbKRCUGaJDkqS1kPbPd7TveP5iyJE0EjAuZQTgFLD2ylzuqKfdKlfG/eSrtxUkn'
-    bootstrap_js_integrity = 'sha384-VHvPCCyXqtD5DqJeNxl2dtTyhF78xXNXdkwX1CZeRusQfRKp+tA7hAShOK/B/fQ2'
+    bootstrap_css_integrity = 'sha384-xOolHFLEh07PJGoPkLv1IbcEPTNtaed2xpHsD9ESMhqIYd0nLMwNLD69Npy4HI+N'
+    bootstrap_js_integrity = 'sha384-+sLIOodYLS7CIrQpBjl+C7nPvqq+FbNUBDunl/OZv93DB7Ln/533i8e/mZXLi/P+'
     jquery_integrity = 'sha256-9/aliU8dGd2tb6OSsuzixeV4y/faTqgFtohetphbbj0='
     popper_integrity = 'sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN'
     popper_name = 'popper.js'

diff --git a/flask_bootstrap/static/bootstrap4/css/bootstrap.min.css b/flask_bootstrap/static/bootstrap4/css/bootstrap.min.css
diff --git a/flask_bootstrap/static/bootstrap4/css/bootstrap.min.css.map b/flask_bootstrap/static/bootstrap4/css/bootstrap.min.css.map
diff --git a/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/_bootswatch.scss b/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/_bootswatch.scss
@@ -1,4 +1,4 @@
-// Cerulean 4.6.1
+// Cerulean 4.6.2
 // Bootswatch
 
 

diff --git a/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/_variables.scss b/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/_variables.scss
@@ -1,4 +1,4 @@
-// Cerulean 4.6.1
+// Cerulean 4.6.2
 // Bootswatch
 
 //

diff --git a/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/bootstrap.css b/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/bootstrap.css
@@ -1,14 +1,14 @@
 /*!
- * Bootswatch v4.6.1
+ * Bootswatch v4.6.2
  * Homepage: https://bootswatch.com
- * Copyright 2012-2021 Thomas Park
+ * Copyright 2012-2022 Thomas Park
  * Licensed under MIT
  * Based on Bootstrap
 */
 /*!
- * Bootstrap v4.6.1 (https://getbootstrap.com/)
- * Copyright 2011-2021 The Bootstrap Authors
- * Copyright 2011-2021 Twitter, Inc.
+ * Bootstrap v4.6.2 (https://getbootstrap.com/)
+ * Copyright 2011-2022 The Bootstrap Authors
+ * Copyright 2011-2022 Twitter, Inc.
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/main/LICENSE)
  */
 :root {
@@ -430,7 +430,7 @@ hr {
 
 small,
 .small {
-  font-size: 80%;
+  font-size: 0.875em;
   font-weight: 400;
 }
 
@@ -470,7 +470,7 @@ mark,
 
 .blockquote-footer {
   display: block;
-  font-size: 80%;
+  font-size: 0.875em;
   color: #868e96;
 }
 
@@ -2228,7 +2228,7 @@ textarea.form-control {
   display: none;
   width: 100%;
   margin-top: 0.25rem;
-  font-size: 80%;
+  font-size: 0.875em;
   color: #73a839;
 }
 
@@ -2339,7 +2339,7 @@ textarea.form-control {
   display: none;
   width: 100%;
   margin-top: 0.25rem;
-  font-size: 80%;
+  font-size: 0.875em;
   color: #c71c22;
 }
 
@@ -3201,6 +3201,18 @@ input[type="button"].btn-block {
   }
 }
 
+.collapsing.width {
+  width: 0;
+  height: auto;
+  transition: width 0.35s ease;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .collapsing.width {
+    transition: none;
+  }
+}
+
 .dropup,
 .dropright,
 .dropdown,
@@ -3792,6 +3804,7 @@ input[type="button"].btn-block {
   padding-left: 1.5rem;
   -webkit-print-color-adjust: exact;
   color-adjust: exact;
+  print-color-adjust: exact;
 }
 
 .custom-control-inline {
@@ -3853,7 +3866,7 @@ input[type="button"].btn-block {
   pointer-events: none;
   content: "";
   background-color: #fff;
-  border: #adb5bd solid 1px;
+  border: 1px solid #adb5bd;
 }
 
 .custom-control-label::after {
@@ -4286,12 +4299,14 @@ input[type="button"].btn-block {
 
 .nav-tabs .nav-link {
   margin-bottom: -1px;
+  background-color: transparent;
   border: 1px solid transparent;
   border-top-left-radius: 0.25rem;
   border-top-right-radius: 0.25rem;
 }
 
 .nav-tabs .nav-link:hover, .nav-tabs .nav-link:focus {
+  isolation: isolate;
   border-color: #e9ecef #e9ecef #dee2e6;
 }
 
@@ -4315,6 +4330,8 @@ input[type="button"].btn-block {
 }
 
 .nav-pills .nav-link {
+  background: none;
+  border: 0;
   border-radius: 0.25rem;
 }
 
@@ -6209,8 +6226,8 @@ a.close.disabled {
   text-transform: none;
   letter-spacing: normal;
   word-break: normal;
-  word-spacing: normal;
   white-space: normal;
+  word-spacing: normal;
   line-break: auto;
   font-size: 0.875rem;
   word-wrap: break-word;
@@ -6322,8 +6339,8 @@ a.close.disabled {
   text-transform: none;
   letter-spacing: normal;
   word-break: normal;
-  word-spacing: normal;
   white-space: normal;
+  word-spacing: normal;
   line-break: auto;
   font-size: 0.875rem;
   word-wrap: break-word;
@@ -6689,7 +6706,7 @@ a.close.disabled {
   width: 2rem;
   height: 2rem;
   vertical-align: -0.125em;
-  border: 0.25em solid currentColor;
+  border: 0.25em solid currentcolor;
   border-right-color: transparent;
   border-radius: 50%;
   -webkit-animation: .75s linear infinite spinner-border;
@@ -6731,7 +6748,7 @@ a.close.disabled {
   width: 2rem;
   height: 2rem;
   vertical-align: -0.125em;
-  background-color: currentColor;
+  background-color: currentcolor;
   border-radius: 50%;
   opacity: 0;
   -webkit-animation: .75s linear infinite spinner-grow;

diff --git a/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/bootstrap.min.css b/flask_bootstrap/static/bootstrap4/css/bootswatch/cerulean/bootstrap.min.css
diff --git a/flask_bootstrap/static/bootstrap4/css/bootswatch/cosmo/_bootswatch.scss b/flask_bootstrap/static/bootstrap4/css/bootswatch/cosmo/_bootswatch.scss
@@ -1,4 +1,4 @@
-// Cosmo 4.6.1
+// Cosmo 4.6.2
 // Bootswatch
 
 

diff --git a/flask_bootstrap/static/bootstrap4/css/bootswatch/cosmo/_variables.scss b/flask_bootstrap/static/bootstrap4/css/bootswatch/cosmo/_variables.scss
@@ -1,4 +1,4 @@
-// Cosmo 4.6.1
+// Cosmo 4.6.2
 // Bootswatch
 
 //