diff --git a/.appveyor.yml b/.appveyor.yml
index 3a7d2f63..11bb6d4b 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -1,16 +1,16 @@
 environment:
   global:
-    TOXENV: py
+    TOXENV: py,codecov
 
   matrix:
-    - PYTHON: C:\Python36
-    - PYTHON: C:\Python27
+    - PYTHON: C:\Python36-x64
+    - PYTHON: C:\Python27-x64
 
 init:
   - SET PATH=%PYTHON%;%PATH%
 
 install:
-  - python -m pip install -U pip setuptools wheel tox
+  - python -m pip install -U tox
 
 build: false
 
@@ -21,3 +21,6 @@ branches:
   only:
     - master
     - /^.*-maintenance$/
+
+cache:
+  - '%LOCALAPPDATA%\pip\Cache'
diff --git a/.travis.yml b/.travis.yml
index 0ff95ecd..b3ba1e19 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,27 +14,30 @@ matrix:
       env: TOXENV=py,codecov
     - python: 2.7
       env: TOXENV=py,simplejson,devel,lowest,codecov
-    - python: pypy
+    - python: pypy3
       env: TOXENV=py,codecov
     - python: nightly
       env: TOXENV=py
     - os: osx
       language: generic
-      env: TOXENV=py
+      env: TOXENV=py3,py2,codecov
+      cache:
+        pip: false
+        directories:
+          - $HOME/Library/Caches/Homebrew
+          - $HOME/Library/Caches/pip
   allow_failures:
+    - python: pypy3
     - python: nightly
-      env: TOXENV=py
     - os: osx
-      language: generic
-      env: TOXENV=py
   fast_finish: true
 
 before_install:
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
-      brew update;
-      brew install python3 redis memcached;
-      virtualenv -p python3 ~/py-env;
-      . ~/py-env/bin/activate;
+  - |
+    if [[ $TRAVIS_OS_NAME == 'osx' ]]; then
+      brew upgrade python
+      brew install python@2;
+      export PATH="/usr/local/opt/python/libexec/bin:${PATH}"
     fi
 
 install:
diff --git a/CHANGES.rst b/CHANGES.rst
index 44fecf55..1902cc85 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -15,6 +15,15 @@ Version 1.0.3
 
 Unreleased
 
+-   :func:`send_file` encodes filenames as ASCII instead of Latin-1
+    (ISO-8859-1). This fixes compatibility with Gunicorn, which is
+    stricter about header encodings than PEP 3333. (`#2766`_)
+-   Allow custom CLIs using ``FlaskGroup`` to set the debug flag without
+    it always being overwritten based on environment variables. (`#2765`_)
+
+.. _#2766: https://github.com/pallets/flask/issues/2766
+.. _#2765: https://github.com/pallets/flask/pull/2765
+
 
 Version 1.0.2
 -------------
diff --git a/docs/installation.rst b/docs/installation.rst
index 15b2f8f7..0014f136 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -132,6 +132,9 @@ Within the activated environment, use the following command to install Flask:
 
     pip install Flask
 
+Flask is now installed. Check out the :doc:`/quickstart` or go to the
+:doc:`Documentation Overview </index>`.
+
 Living on the edge
 ~~~~~~~~~~~~~~~~~~
 
@@ -177,7 +180,7 @@ On Windows, as an administrator:
     \Python27\python.exe Downloads\get-pip.py
     \Python27\python.exe -m pip install virtualenv
 
-Now you can continue to :ref:`install-create-env`.
+Now you can return above and :ref:`install-create-env`.
 
 .. _virtualenv: https://virtualenv.pypa.io/
 .. _get-pip.py: https://bootstrap.pypa.io/get-pip.py
diff --git a/flask/cli.py b/flask/cli.py
index fa006c57..b3066477 100644
--- a/flask/cli.py
+++ b/flask/cli.py
@@ -340,7 +340,8 @@ class ScriptInfo(object):
     onwards as click object.
     """
 
-    def __init__(self, app_import_path=None, create_app=None):
+    def __init__(self, app_import_path=None, create_app=None,
+                 set_debug_flag=True):
         #: Optionally the import path for the Flask application.
         self.app_import_path = app_import_path or os.environ.get('FLASK_APP')
         #: Optionally a function that is passed the script info to create
@@ -349,6 +350,7 @@ class ScriptInfo(object):
         #: A dictionary with arbitrary data that can be associated with
         #: this script info.
         self.data = {}
+        self.set_debug_flag = set_debug_flag
         self._loaded_app = None
 
     def load_app(self):
@@ -386,12 +388,10 @@ class ScriptInfo(object):
                 '"app.py" module was not found in the current directory.'
             )
 
-        debug = get_debug_flag()
-
-        # Update the app's debug flag through the descriptor so that other
-        # values repopulate as well.
-        if debug is not None:
-            app.debug = debug
+        if self.set_debug_flag:
+            # Update the app's debug flag through the descriptor so that
+            # other values repopulate as well.
+            app.debug = get_debug_flag()
 
         self._loaded_app = app
         return app
@@ -459,6 +459,8 @@ class FlaskGroup(AppGroup):
     :param load_dotenv: Load the nearest :file:`.env` and :file:`.flaskenv`
         files to set environment variables. Will also change the working
         directory to the directory containing the first file found.
+    :param set_debug_flag: Set the app's debug flag based on the active
+        environment
 
     .. versionchanged:: 1.0
         If installed, python-dotenv will be used to load environment variables
@@ -466,7 +468,8 @@ class FlaskGroup(AppGroup):
     """
 
     def __init__(self, add_default_commands=True, create_app=None,
-                 add_version_option=True, load_dotenv=True, **extra):
+                 add_version_option=True, load_dotenv=True,
+                 set_debug_flag=True, **extra):
         params = list(extra.pop('params', None) or ())
 
         if add_version_option:
@@ -475,6 +478,7 @@ class FlaskGroup(AppGroup):
         AppGroup.__init__(self, params=params, **extra)
         self.create_app = create_app
         self.load_dotenv = load_dotenv
+        self.set_debug_flag = set_debug_flag
 
         if add_default_commands:
             self.add_command(run_command)
@@ -550,7 +554,8 @@ class FlaskGroup(AppGroup):
         obj = kwargs.get('obj')
 
         if obj is None:
-            obj = ScriptInfo(create_app=self.create_app)
+            obj = ScriptInfo(create_app=self.create_app,
+                             set_debug_flag=self.set_debug_flag)
 
         kwargs['obj'] = obj
         kwargs.setdefault('auto_envvar_prefix', 'FLASK')
@@ -670,7 +675,7 @@ class CertParamType(click.ParamType):
 
             obj = import_string(value, silent=True)
 
-            if sys.version_info < (2, 7):
+            if sys.version_info < (2, 7, 9):
                 if obj:
                     return obj
             else:
@@ -687,7 +692,7 @@ def _validate_key(ctx, param, value):
     cert = ctx.params.get('cert')
     is_adhoc = cert == 'adhoc'
 
-    if sys.version_info < (2, 7):
+    if sys.version_info < (2, 7, 9):
         is_context = cert and not isinstance(cert, (text_type, bytes))
     else:
         is_context = isinstance(cert, ssl.SSLContext)
diff --git a/flask/helpers.py b/flask/helpers.py
index df0b91fc..7679a496 100644
--- a/flask/helpers.py
+++ b/flask/helpers.py
@@ -506,6 +506,10 @@ def send_file(filename_or_fp, mimetype=None, as_attachment=False,
 
     .. _RFC 2231: https://tools.ietf.org/html/rfc2231#section-4
 
+    .. versionchanged:: 1.0.3
+        Filenames are encoded with ASCII instead of Latin-1 for broader
+        compatibility with WSGI servers.
+
     :param filename_or_fp: the filename of the file to send.
                            This is relative to the :attr:`~Flask.root_path`
                            if a relative path is specified.
@@ -564,11 +568,11 @@ def send_file(filename_or_fp, mimetype=None, as_attachment=False,
                             'sending as attachment')
 
         try:
-            attachment_filename = attachment_filename.encode('latin-1')
+            attachment_filename = attachment_filename.encode('ascii')
         except UnicodeEncodeError:
             filenames = {
                 'filename': unicodedata.normalize(
-                    'NFKD', attachment_filename).encode('latin-1', 'ignore'),
+                    'NFKD', attachment_filename).encode('ascii', 'ignore'),
                 'filename*': "UTF-8''%s" % url_quote(attachment_filename),
             }
         else:
diff --git a/tests/test_cli.py b/tests/test_cli.py
index f7ebc6bd..83151f6f 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -356,6 +356,28 @@ def test_flaskgroup(runner):
     assert result.output == 'flaskgroup\n'
 
 
+@pytest.mark.parametrize('set_debug_flag', (True, False))
+def test_flaskgroup_debug(runner, set_debug_flag):
+    """Test FlaskGroup debug flag behavior."""
+
+    def create_app(info):
+        app = Flask("flaskgroup")
+        app.debug = True
+        return app
+
+    @click.group(cls=FlaskGroup, create_app=create_app, set_debug_flag=set_debug_flag)
+    def cli(**params):
+        pass
+
+    @cli.command()
+    def test():
+        click.echo(str(current_app.debug))
+
+    result = runner.invoke(cli, ['test'])
+    assert result.exit_code == 0
+    assert result.output == '%s\n' % str(not set_debug_flag)
+
+
 def test_print_exceptions(runner):
     """Print the stacktrace if the CLI."""
 
@@ -537,12 +559,12 @@ def test_run_cert_import(monkeypatch):
         run_command.make_context('run', ['--cert', 'not_here'])
 
     # not an SSLContext
-    if sys.version_info >= (2, 7):
+    if sys.version_info >= (2, 7, 9):
         with pytest.raises(click.BadParameter):
             run_command.make_context('run', ['--cert', 'flask'])
 
     # SSLContext
-    if sys.version_info < (2, 7):
+    if sys.version_info < (2, 7, 9):
         ssl_context = object()
     else:
         ssl_context = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index b3535b28..ae1c0805 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -638,15 +638,22 @@ class TestSendfile(object):
         assert options['filename'] == 'index.txt'
         rv.close()
 
-    def test_attachment_with_utf8_filename(self, app, req_ctx):
-        rv = flask.send_file('static/index.html', as_attachment=True, attachment_filename=u'Ñandú／pingüino.txt')
-        content_disposition = set(rv.headers['Content-Disposition'].split('; '))
-        assert content_disposition == set((
-            'attachment',
-            'filename="Nandu/pinguino.txt"',
-            "filename*=UTF-8''%C3%91and%C3%BA%EF%BC%8Fping%C3%BCino.txt"
-        ))
+    @pytest.mark.usefixtures('req_ctx')
+    @pytest.mark.parametrize(('filename', 'ascii', 'utf8'), (
+        ('index.html', 'index.html', False),
+        (u'Ñandú／pingüino.txt', '"Nandu/pinguino.txt"',
+        '%C3%91and%C3%BA%EF%BC%8Fping%C3%BCino.txt'),
+        (u'Vögel.txt', 'Vogel.txt', 'V%C3%B6gel.txt'),
+    ))
+    def test_attachment_filename_encoding(self, filename, ascii, utf8):
+        rv = flask.send_file('static/index.html', as_attachment=True, attachment_filename=filename)
         rv.close()
+        content_disposition = rv.headers['Content-Disposition']
+        assert 'filename=%s' % ascii in content_disposition
+        if utf8:
+            assert "filename*=UTF-8''" + utf8 in content_disposition
+        else:
+            assert "filename*=UTF-8''" not in content_disposition
 
     def test_static_file(self, app, req_ctx):
         # default cache timeout is 12 hours
diff --git a/tox.ini b/tox.ini
index 03e53d90..546b9279 100644
--- a/tox.ini
+++ b/tox.ini
@@ -60,7 +60,7 @@ commands =
     coverage html
 
 [testenv:codecov]
-passenv = CI TRAVIS TRAVIS_*
+passenv = CI TRAVIS TRAVIS_* APPVEYOR APPVEYOR_*
 deps = codecov
 skip_install = true
 commands =