diff --git a/KerbalStuff/blueprints/api.py b/KerbalStuff/blueprints/api.py
index 53ae2daa..c41eadbf 100644
--- a/KerbalStuff/blueprints/api.py
+++ b/KerbalStuff/blueprints/api.py
@@ -935,6 +935,13 @@ def update_mod(mod_id: int) -> Tuple[Dict[str, Any], int]:
                           'Did you mistype the version number?'
             }, 400
 
+    changelog: Optional[str] = request.form.get('changelog')
+    if changelog and len(changelog) > ModVersion.changelog.type.length:
+        return {'error': True, 'reason': f'Changelog is {len(changelog)} bytes, the limit is {ModVersion.changelog.type.length}!'}, 400
+    changelog_html = render_markdown(changelog)
+    if changelog_html and len(changelog_html) > ModVersion.changelog_html.type.length:
+        return {'error': True, 'reason': f'Rendered changelog is {len(changelog_html)} bytes, the limit is {ModVersion.changelog_html.type.length}!'}, 400
+
     full_path, relative_path = _get_modversion_paths(mod.name, friendly_version)
     how_many_chunks = int(request.form.get('dztotalchunkcount', 1))
     which_chunk = int(request.form.get('dzchunkindex', 0))
@@ -955,14 +962,13 @@ def update_mod(mod_id: int) -> Tuple[Dict[str, Any], int]:
         if file_contains_malware(full_path):
             quarantine_malware(full_path)
             punish_malware(current_user)
-            return {'error': True, 'reason': f'Malware detected in upload'}, 400
+            return {'error': True, 'reason': 'Malware detected in upload'}, 400
 
-        changelog: Optional[str] = request.form.get('changelog')
         version = ModVersion(friendly_version=friendly_version,
                              gameversion_id=game_version.id,
                              download_path=relative_path,
                              changelog=changelog,
-                             changelog_html=render_markdown(changelog))
+                             changelog_html=changelog_html)
         # Assign a sort index
         if mod.versions:
             version.sort_index = max(v.sort_index for v in mod.versions) + 1
@@ -1001,8 +1007,14 @@ def edit_version(mod_id: int) -> Tuple[Dict[str, Any], int]:
     if len(versions) == 0:
         return {'error': True, 'reason': 'Version not found'}, 404
     version = versions[0]
-    version.changelog = request.form.get('changelog')
-    version.changelog_html = render_markdown(version.changelog)
+    changelog: Optional[str] = request.form.get('changelog')
+    if changelog and len(changelog) > ModVersion.changelog.type.length:
+        return {'error': True, 'reason': f'Changelog is {len(changelog)} bytes, the limit is {ModVersion.changelog.type.length}!'}, 400
+    changelog_html = render_markdown(changelog)
+    if changelog_html and len(changelog_html) > ModVersion.changelog_html.type.length:
+        return {'error': True, 'reason': f'Rendered changelog is {len(changelog_html)} bytes, the limit is {ModVersion.changelog_html.type.length}!'}, 400
+    version.changelog = changelog
+    version.changelog_html = changelog_html
     mod.updated = datetime.now()
 
     # Handle the chunks if sent
diff --git a/KerbalStuff/blueprints/mods.py b/KerbalStuff/blueprints/mods.py
index 4b8f4836..3229dc61 100644
--- a/KerbalStuff/blueprints/mods.py
+++ b/KerbalStuff/blueprints/mods.py
@@ -683,7 +683,7 @@ def delete_version(mod_id: int, version_id: str) -> werkzeug.wrappers.Response:
     if version.mod != mod:
         abort(400)
 
-    purge_download(version[0].download_path)
+    purge_download(version.download_path)
 
     storage = _cfg('storage')
     if storage:
diff --git a/KerbalStuff/common.py b/KerbalStuff/common.py
index 794c3caa..d470fd8f 100644
--- a/KerbalStuff/common.py
+++ b/KerbalStuff/common.py
@@ -47,7 +47,7 @@ def allow_iframe_attr(tagname: str, attrib: str, val: str) -> bool:
                              'iframe': allow_iframe_attr
                          },
                          css_sanitizer=CSSSanitizer(),
-                         filters=[bleach.linkifier.LinkifyFilter])
+                         filters=[bleach.linkifier.LinkifyFilter])  # type: ignore[list-item]
 
 
 def first_paragraphs(text: Optional[str]) -> str:
diff --git a/docker-compose-prod.yml b/docker-compose-prod.yml
index 0a80f857..d07657d8 100644
--- a/docker-compose-prod.yml
+++ b/docker-compose-prod.yml
@@ -1,5 +1,3 @@
-version: "3.4"
-
 services:
   db:
     image: postgres:11
diff --git a/docker-compose.yml b/docker-compose.yml
index e49e003d..8eb8b118 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,5 +1,3 @@
-version: "3.4"
-
 services:
   db:
     image: postgres:11
diff --git a/frontend/coffee/update.coffee b/frontend/coffee/update.coffee
index 243671e2..19f92947 100644
--- a/frontend/coffee/update.coffee
+++ b/frontend/coffee/update.coffee
@@ -3,16 +3,20 @@ editor.render()
 
 Dropzone = require('dropzone').Dropzone
 
-error = (name) ->
+error = (name, htmlMsg) ->
     document.getElementById(name).parentElement.classList.add('has-error')
     document.getElementById('error-alert').classList.remove('hidden')
+    alert = $("#error-alert")
+    alert.html if alert.text() == '' then alert.html().concat(htmlMsg) else alert.html().concat("<br/>").concat(htmlMsg)
 
 valid = ->
     a.classList.remove('has-error') for a in document.querySelectorAll('.has-error')
     document.getElementById('error-alert').classList.add('hidden')
+    $("#error-alert").text('')
 
-    error('version') if $("#version").val() == ''
-    error('uploader') if Dropzone.forElement('#uploader').files.length != 1
+    error('version', 'Version is required!') if $("#version").val() == ''
+    error('uploader', 'No file uploaded!') if Dropzone.forElement('#uploader').files.length != 1
+    error('changelog', "Changelog is #{editor.codemirror.getValue().length} bytes, the limit is 10000!") if editor.codemirror.getValue().length > 10000
 
     return document.querySelectorAll('.has-error').length == 0