diff --git a/archivebox/config.py b/archivebox/config.py
index fbcbca03..c8a40c30 100644
--- a/archivebox/config.py
+++ b/archivebox/config.py
@@ -426,7 +426,7 @@ def get_version_releases(config):
     # find upgrade version
     upgrade_version = None
     smallest_version_diff = parse_tag_name(releases[0]["tag_name"])[1]
-    for i, release in enumerate(releases):
+    for release in releases:
         release_parts = parse_tag_name(release["tag_name"])
         major_version_diff = release_parts[1] - installed_version_parts[1]
         if major_version_diff < smallest_version_diff:
@@ -750,9 +750,9 @@ def load_config(defaults: ConfigDefaultDict,
 
 def parse_tag_name(v):
     """parses a version tag string formatted like 'vx.x.x'"""
-    v = re.sub(r"\+.*$", "", v) # in case version string ends with '+editable'
-    parts = re.sub(r"^v", "", v).split(".")
-    return [int(p) for p in parts]
+    base = v.split('+')[0].split('v')[-1] # remove 'v' prefix and '+editable' suffix
+    int_parts = [int(part) for part in base.split('.')]
+    return int_parts
 
 
 def compare_versions(v1, v2):
diff --git a/archivebox/templates/admin/base.html b/archivebox/templates/admin/base.html
index 5e84d9bc..7c31d83a 100644
--- a/archivebox/templates/admin/base.html
+++ b/archivebox/templates/admin/base.html
@@ -142,11 +142,12 @@
         </div>
 
         <script>
-            if ("{{CAN_UPGRADE}}" === "True" && !localStorage.getItem("bannerDismissed")) {
-                let upgradeVersionTag = "{{VERSION_RELEASES.upgrade_version.tag_name}}"
+            {% if user.is_authenticated and CAN_UPGRADE %}
+            if (!localStorage.getItem("bannerDismissed")) {
+                const upgradeVersionTag = "{{VERSION_RELEASES.upgrade_version.tag_name}}"
                 const upgradeVersionURL = "{{VERSION_RELEASES.upgrade_version.html_url}}"
-                let currentVersionTag = "{{VERSION}}"
-                let currentVersionURL = "{{VERSION_RELEASES.current_version.html_url}}"
+                const currentVersionTag = "{{VERSION}}"
+                const currentVersionURL = "{{VERSION_RELEASES.current_version.html_url}}"
 
                 createBanner(currentVersionTag, currentVersionURL, upgradeVersionTag, upgradeVersionURL)
             }
@@ -174,6 +175,7 @@
                 banner.style.display = "none"
                 localStorage.setItem("bannerDismissed", "true")
             }
+            {% endif %}
 
             $ = django.jQuery;
             $.fn.reverse = [].reverse;