diff --git a/web_company_color/__manifest__.py b/web_company_color/__manifest__.py
index 1f30c4e8af3..1a2280bed99 100644
--- a/web_company_color/__manifest__.py
+++ b/web_company_color/__manifest__.py
@@ -5,7 +5,7 @@
 {
     "name": "Web Company Color",
     "category": "web",
-    "version": "18.0.1.1.0",
+    "version": "18.0.1.1.1",
     "author": "Alexandre Díaz, Odoo Community Association (OCA)",
     "website": "https://github.com/OCA/web",
     "depends": ["web", "base_sparse_field"],
diff --git a/web_company_color/migrations/18.0.1.1.1/post-migration.py b/web_company_color/migrations/18.0.1.1.1/post-migration.py
new file mode 100644
index 00000000000..0e510f76a39
--- /dev/null
+++ b/web_company_color/migrations/18.0.1.1.1/post-migration.py
@@ -0,0 +1,22 @@
+# Copyright NuoBiT Solutions - Eric Antones <eantones@nuobit.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl)
+from odoo import SUPERUSER_ID, api
+
+
+def migrate(cr, version):
+    """Regenerate the per-company color attachments in the current format.
+
+    Databases upgraded from older versions still carry the color
+    attachments in the legacy format (raw SCSS content, mimetype
+    ``application/octet-stream``). The current module compiles the SCSS
+    server-side and serves the attachment URL directly as a stylesheet,
+    so it needs compiled CSS with mimetype ``text/css`` — browsers refuse
+    the legacy attachments under strict MIME checking and company colors
+    silently stop applying. Only the ``post_init_hook`` (fresh installs)
+    regenerates them; upgrades never did. Idempotent: regenerating an
+    up-to-date attachment rewrites it with identical semantics.
+    """
+    if not version:
+        return
+    env = api.Environment(cr, SUPERUSER_ID, {})
+    env["res.company"].search([]).scss_create_or_update_attachment()