diff --git a/cms/envs/common.py b/cms/envs/common.py
index a8ba7ef032..d5ea6b47bd 100644
--- a/cms/envs/common.py
+++ b/cms/envs/common.py
@@ -387,6 +387,23 @@ FEATURES = {
     # .. toggle_status: supported
     # .. toggle_warnings: None
     'ENABLE_ORA_USER_STATE_UPLOAD_DATA': False,
+
+    # .. toggle_name: DEPRECATE_OLD_COURSE_KEYS_IN_STUDIO
+    # .. toggle_implementation: DjangoSetting
+    # .. toggle_default: True
+    # .. toggle_description: Warn about removing support for deprecated course keys.
+    #      To enable, set to True.
+    #      To disable, set to False.
+    #      To enable with a custom support deadline, set to an ISO-8601 date string:
+    #        eg: '2020-09-01'
+    # .. toggle_category: n/a
+    # .. toggle_use_cases: incremental_release
+    # .. toggle_creation_date: 2020-06-12
+    # .. toggle_expiration_date: 2020-09-01
+    # .. toggle_warnings: This can be removed once support is removed for deprecated course keys.
+    # .. toggle_tickets: https://openedx.atlassian.net/browse/DEPR-58
+    # .. toggle_status: supported
+    'DEPRECATE_OLD_COURSE_KEYS_IN_STUDIO': True,
 }
 
 ENABLE_JASMINE = False
diff --git a/cms/templates/base.html b/cms/templates/base.html
index c8d2a33309..dacdb55a71 100644
--- a/cms/templates/base.html
+++ b/cms/templates/base.html
@@ -118,6 +118,7 @@ from openedx.core.release import RELEASE_LINE
       % endif
 
       <div id="page-alert">
+        <%include file="widgets/deprecated-course-key-warning.html" args="course=context_course" />
       <%block name="page_alert"></%block>
       </div>
 
diff --git a/cms/templates/widgets/deprecated-course-key-warning.html b/cms/templates/widgets/deprecated-course-key-warning.html
new file mode 100644
index 0000000000..80aa94b9c6
--- /dev/null
+++ b/cms/templates/widgets/deprecated-course-key-warning.html
@@ -0,0 +1,49 @@
+<%page args="course=None" expression_filter="h" />
+<%!
+from datetime import datetime
+from datetime import date
+
+from django.conf import settings
+from django.utils.translation import ugettext as _
+
+from openedx.core.djangolib.translation_utils import translate_date
+
+DEFAULT_LANGUAGE = getattr(settings, 'LANGUAGE_CODE', 'en')
+IS_ENABLED = settings.FEATURES.get('DEPRECATE_OLD_COURSE_KEYS_IN_STUDIO', True)
+%>
+<%
+is_visible = IS_ENABLED and course and course.id.deprecated
+if is_visible:
+    try:
+        expiration_date = datetime.strptime(IS_ENABLED, "%Y-%m-%d")
+    except TypeError as error:
+        expiration_message = _('Support will be removed in an upcoming release.')
+    else:
+        language = getattr(course, 'language', None) or DEFAULT_LANGUAGE
+        expiration_date = date(expiration_date.year, expiration_date.month, expiration_date.day)
+        expiration_date = translate_date(expiration_date, language=language)
+        expiration_message = _("Support will be removed on {expiration_date}.").format(
+            expiration_date=expiration_date,
+        )
+    is_visible = True
+%>
+% if is_visible:
+  <div class="wrapper wrapper-alert wrapper-alert-warning is-shown">
+    <div class="alert announcement">
+      <span class="feedback-symbol fa fa-warning" aria-hidden="true"></span>
+      <span class="sr">${_("Warning")}</span>
+      <div class="copy">
+        <h2 class="title title-3 warning-heading-text">
+          ${_("This course uses a legacy storage format.")}
+        </h2>
+        <p>
+          ${expiration_message}
+          ${_(
+            "Please reach out to your support team contact, "
+            "if you have any additional questions or concerns."
+          )}
+        </p>
+      </div>
+    </div>
+  </div>
+% endif