diff --git a/content/pages/04-web-development/03-flask.markdown b/content/pages/04-web-development/03-flask.markdown
index fd7625f0e..98b4b45c7 100644
--- a/content/pages/04-web-development/03-flask.markdown
+++ b/content/pages/04-web-development/03-flask.markdown
@@ -332,6 +332,12 @@ ways to structure your code.
   combines a Flask framework project structure with 
   [Webpack](https://webpack.js.org/), a module bundler frequently used
   in the JavaScript world.
+    
+* [Bootstrap-Flask](https://github.com/helloflask/bootstrap-flask) is a
+  collection of Jinja macros for [Bootstrap](/bootstrap-css.html) 4 & 5 and
+  Flask. It helps rendering Flask-related data and objects to Bootstrap markup
+  HTML more easily. Check the [demo](http://bootstrapflaskdemo5.nsupdate.info/)
+  for the versions of Bootstrap it supports.
 
 
 ## Open source code for learning Flask
diff --git a/content/pages/04-web-development/21-bootstrap.markdown b/content/pages/04-web-development/21-bootstrap.markdown
index 97c4db1fa..fa3b4ebe0 100644
--- a/content/pages/04-web-development/21-bootstrap.markdown
+++ b/content/pages/04-web-development/21-bootstrap.markdown
@@ -35,6 +35,9 @@ customized with my own CSS that I likely will never upgrade to Bootstrap 4
 because there are no new features that I feel will be useful in my
 specific situation.
 
+In May 2021, Bootstrap 5 has been released. It has many improvements and
+additions compared to version 4.
+
 
 ### Bootstrap resources
 * [Getting Started with Bootstrap](https://realpython.com/blog/python/getting-started-with-bootstrap-3/)
@@ -68,3 +71,9 @@ specific situation.
   ([source code](https://github.com/react-bootstrap/react-bootstrap) replaces
   the existing Bootstrap JavaScript with React components that do not
   rely on jQuery.
+  
+* [Bootstrap-Flask](https://github.com/helloflask/bootstrap-flask) is a
+  collection of Jinja macros for Bootstrap 4 & 5 and [Flask](/flask.html). It
+  helps rendering Flask-related data and objects to Bootstrap markup HTML more
+  easily. Check the [demo](http://bootstrapflaskdemo5.nsupdate.info/) for the
+  versions of Bootstrap it supports.