diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a6ab588ed0..540ee31103 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,10 +1,10 @@
 # Contributing
 
-Thank you for your interest in contributing to plotly.py! We are actively looking for
+Thank you for your interest in contributing to Plotly.py! We are actively looking for
 diverse contributors, with diverse background and skills.
 
 This guide starts with a general description of the different ways to contribute
-to plotly.py, then we explain some technical aspects of preparing your
+to Plotly.py, then we explain some technical aspects of preparing your
 contribution.
 
 ## Code of Conduct
@@ -14,7 +14,7 @@ but the general idea is to be nice.
 
 ## What are the different ways to contribute?
 
-There are many ways to contribute to plotly.py. To contribute effectively, it is important to first gain an understanding of the structure of the code and of the repository.
+There are many ways to contribute to Plotly.py. To contribute effectively, it is important to first gain an understanding of the structure of the code and of the repository.
 
 - [the `plotly.graph_objects` module](https://plotly.com/python/graph-objects/) (usually imported as `go`)
   is [generated from the Plotly.js schema](https://plotly.com/python/figure-structure/),
@@ -79,7 +79,7 @@ also contribute to the project by
 
 - helping other users on the [community forum](https://community.plot.ly/).
   Join the list of [nice people](https://community.plot.ly/u) helping other
-  plotly users :-).
+  Plotly users :-).
 
 We also recommend reading the great
 [how to contribute to open source](https://opensource.guide/how-to-contribute/)
@@ -93,7 +93,7 @@ Open an issue! Go to https://github.com/plotly/plotly.py/issues. It's possible t
 
 Check out our Community Forum: https://community.plot.ly/.
 
-## Want to improve the plotly documentation?
+## Want to improve the Plotly documentation?
 
 Thank you! Instructions on how to contribute to the documentation are given [here](doc/README.md). Please also read the next section if you need to setup a development environment.
 
@@ -121,16 +121,16 @@ cd plotly.py
 Note: if you're just getting started with git, there exist great resources to
 learn and become confident about git, like http://try.github.io/.
 
-### Create a virtual environment for plotly development
+### Create a virtual environment for Plotly development
 
-You can use either [conda][conda-env] or [virtualenv][virtualenv] to create a virtual environment for plotly development, e.g.:
+You can use either [conda][conda-env] or [virtualenv][virtualenv] to create a virtual environment for Plotly development, e.g.:
 
 ```bash
 conda create -n plotly-dev python=3.11
 conda activate plotly-dev
 ```
 
-As of May 2024 our dependencies have been tested against Python versions 3.8 to 3.11.
+As of June 2025, Plotly is tested against Python versions 3.8 to 3.13.
 We will support Python 3.12 and higher versions soon.
 
 [conda-env]: https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html#creating-an-environment-with-commands
@@ -149,7 +149,7 @@ complete installation and avoid gdal-config errors.
 (plotly_dev) $ pip install -r requires-optional.txt
 ```
 
-### Editable install of plotly packages
+### Editable install of Plotly packages
 ```bash
 (plotly_dev) $ pip install -e .
 ```
diff --git a/requires-optional.txt b/requires-optional.txt
deleted file mode 100644
index a772dedd87..0000000000
--- a/requires-optional.txt
+++ /dev/null
@@ -1,56 +0,0 @@
-### Optional Dependencies for Additional Plotly Functionality   ###
-###                                                             ###
-### This file lists packages which are not strictly required    ###
-### by Plotly.py, but which are needed to use some of the       ###
-### library's functionality. See headings below for more        ###
-### See headings below for more detail.                         ###
-###                                                             ###
-### Packages used in the development process are also listed    ###
-### here.                                                       ###
-###                                                             ###
-### To install, run:                                            ###
-###      $ pip install -r requires-optional.txt                 ###
-###                                                             ###
-###################################################################
-
-## numpy (required by Plotly Express) ##
-numpy
-
-## matplotlylib dependencies ##
-# matplotlib==2.2.2
-
-## testing dependencies ##
-# see also test_requirements/*.txt for specific Python versions
-coverage==4.3.1
-mock==2.0.0
-pytest==8.1.1
-xarray
-pytz
-
-## code formatting ##
-pre-commit
-black==22.3.0
-
-## codegen dependencies ##
-inflect
-
-## template generation ##
-colorcet
-
-## pandas (for some matplotlib functionality) ##
-pandas
-
-## scipy deps (for some Figure Factory functions) ##
-scipy
-
-## jupyter ##
-jupyter
-anywidget
-
-## deps for _county_choropleth.py (Figure Factory) ##
-pyshp
-geopandas
-shapely
-
-## image uri conversion ##
-pillow