diff --git a/.gitignore b/.gitignore
index 7793188..18ebf07 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,13 +1,137 @@
-*.pyc
-.svn
-.project
-.pydevproject
-.vscode
-/dist
-/build
-/django_paypal.egg-info
-*.swp
-.tox
-.idea/
-docs/_build
-.DS_Store
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# vscode
+.vscode/
diff --git a/docs/standard/ipn.rst b/docs/standard/ipn.rst
index eb8f422..7b567c3 100644
--- a/docs/standard/ipn.rst
+++ b/docs/standard/ipn.rst
@@ -69,7 +69,7 @@ Using PayPal Standard IPN
 
 
    For a full list of variables that can be used in ``paypal_dict``, see
-   `PayPal HTML variables documentation <https://developer.paypal.com/webapps/developer/docs/classic/paypal-payments-standard/integration-guide/Appx_websitestandard_htmlvariables/>`_.
+   `PayPal HTML variables documentation <https://developer.paypal.com/api/nvp-soap/paypal-payments-standard/integration-guide/Appx-websitestandard-htmlvariables/>`_.
 
    .. note:: The names of these variables are not the same as the values
              returned on the IPN object.
@@ -87,6 +87,18 @@ Using PayPal Standard IPN
    by subclassing ``PayPalPaymentsForm`` and overriding the ``get_image``
    method.
 
+   **Submit button customisation**
+   The submit button used by the form is the standard PayPal payment button, but it's possible to customise it extending the form:
+
+   .. code-block:: python
+
+       from paypal.standard.forms import PayPalPaymentsForm
+
+       class CustomPayPalPaymentsForm(PayPalPaymentsForm):
+
+           def get_html_submit_element(self):
+               return """<button type="submit">Continue on PayPal website</button>"""
+
 4. When someone uses this button to buy something PayPal makes a HTTP POST to
    your "notify_url". PayPal calls this Instant Payment Notification (IPN).
    The view ``paypal.standard.ipn.views.ipn`` handles IPN processing. To set the
diff --git a/paypal/standard/forms.py b/paypal/standard/forms.py
index 38cec99..66d3028 100644
--- a/paypal/standard/forms.py
+++ b/paypal/standard/forms.py
@@ -191,20 +191,26 @@ def get_login_url(self):
         else:
             return LOGIN_URL
 
+    def get_html(self):
+        return format_html(
+            """<form action="{0}" method="post">{1}{2}</form>""",
+            self.get_login_url(),
+            self.as_p(),
+            self.get_html_submit_element(),
+        )
+
+    def get_html_submit_element(self):
+        return format_html(
+            """<input type="image" src="{0}" name="submit" alt="Buy it Now" />""",
+            self.get_image(),
+        )
+
     if DJANGO_FORM_HAS_RENDER_METHOD:
 
         def render(self, *args, **kwargs):
             if not args and not kwargs:
                 # `form.render` usage from template
-                return format_html(
-                    """<form action="{0}" method="post">
-    {1}
-    <input type="image" src="{2}" name="submit" alt="Buy it Now" />
-</form>""",
-                    self.get_login_url(),
-                    self.as_p(),
-                    self.get_image(),
-                )
+                return self.get_html()
             else:
                 # Need to delegate to super. This provides
                 # support for `as_p` method and for `BoundField.label_tag`,
@@ -214,15 +220,7 @@ def render(self, *args, **kwargs):
     else:
 
         def render(self):
-            return format_html(
-                """<form action="{0}" method="post">
-    {1}
-    <input type="image" src="{2}" name="submit" alt="Buy it Now" />
-</form>""",
-                self.get_login_url(),
-                self.as_p(),
-                self.get_image(),
-            )
+            return self.get_html()
 
     def get_image(self):
         return {