diff --git a/k9-svc/GUIDE.adoc b/k9-svc/GUIDE.adoc
index acf22779..37139779 100644
--- a/k9-svc/GUIDE.adoc
+++ b/k9-svc/GUIDE.adoc
@@ -162,7 +162,7 @@ let component_pedigree = {
   metadata = {
     name = "example-config",
     version = "1.0.0",
-    breed = "application/vnd.k9+nickel",
+    breed = "application/vnd.k9",
     magic_number = "K9!",
   },
   security = {
diff --git a/k9-svc/README.adoc b/k9-svc/README.adoc
index f692f038..c66b50d4 100644
--- a/k9-svc/README.adoc
+++ b/k9-svc/README.adoc
@@ -188,7 +188,7 @@ K9 takes security seriously. Self-executing components require careful design an
 |`K9!` (`\x4B\x39\x21`)
 
 |MIME Type
-|`application/vnd.k9+nickel`
+|`application/vnd.k9`
 
 |Extensions
 |`.k9`, `.k9.ncl`
diff --git a/k9-svc/SPEC.adoc b/k9-svc/SPEC.adoc
index dde5bd8b..5b3fe998 100644
--- a/k9-svc/SPEC.adoc
+++ b/k9-svc/SPEC.adoc
@@ -31,7 +31,7 @@ word `must` appears in both and means different things; never conflate them.
 
 [cols="1,2"]
 |===
-|Standard ID |`application/vnd.k9+nickel`
+|Standard ID |`application/vnd.k9`
 |Version |1.0.0
 |Stability |Stable
 |Magic Number |`K9!` (`\x4B\x39\x21`)
@@ -359,7 +359,7 @@ To be listed as a conforming `.k9` repository:
 
 [source,xml]
 ----
-<mime-type type="application/vnd.k9+nickel">
+<mime-type type="application/vnd.k9">
   <comment>K9 Self-Validating Component</comment>
   <magic priority="50">
     <match value="K9!" type="string" offset="0"/>
@@ -377,7 +377,7 @@ Location: `/usr/share/mime/packages/k9.xml`
 <key>UTTypeIdentifier</key>
 <string>org.k9-svc.component</string>
 <key>public.mime-type</key>
-<string>application/vnd.k9+nickel</string>
+<string>application/vnd.k9</string>
 ----
 
 === Minix
@@ -386,7 +386,7 @@ Static mapping in `/etc/mime.types`:
 
 [source]
 ----
-application/vnd.k9+nickel    k9
+application/vnd.k9    k9
 ----
 
 == Philosophy
diff --git a/k9-svc/docs/IANA-MEDIA-TYPE.adoc b/k9-svc/docs/IANA-MEDIA-TYPE.adoc
index 7fea5a2f..778ad189 100644
--- a/k9-svc/docs/IANA-MEDIA-TYPE.adoc
+++ b/k9-svc/docs/IANA-MEDIA-TYPE.adoc
@@ -1,6 +1,22 @@
 // SPDX-License-Identifier: CC-BY-SA-4.0
 = IANA Media Type Registration: application/vnd.k9+nickel
 
+[WARNING]
+====
+*SUPERSEDED (2026-09-01) — historical record only.*
+
+This document registers `application/vnd.k9+nickel`. That form was withdrawn:
+the current application registers *`application/vnd.k9`*, without a
+structured-syntax suffix. Structured-syntax suffixes are intended for widely
+registered base syntaxes, and `+nickel` is not one.
+
+*What replaced it:* link:../IANA-MEDIA-TYPE-APPLICATION.adoc[`IANA-MEDIA-TYPE-APPLICATION.adoc`].
+
+The `+nickel` form remains reserved as a possible future companion type. The
+text below is retained unedited for provenance — do not cite it as current.
+====
+
+
 This is the formal IANA media type registration for K9 SVC (Self-Validating Component) format.
 
 [source]
diff --git a/k9-svc/pedigree.ncl b/k9-svc/pedigree.ncl
index 00183320..77987660 100644
--- a/k9-svc/pedigree.ncl
+++ b/k9-svc/pedigree.ncl
@@ -29,7 +29,7 @@ let Architecture = [| 'Linux, 'Minix, 'MacOS, 'Android, 'PC, 'ASIC, 'Unknown |]
   Metadata = {
     name | String,
     version | String | default = "1.0.0",
-    breed | String | default = "application/vnd.k9+nickel",
+    breed | String | default = "application/vnd.k9",
     magic_number | String | default = "K9!",
     description | String | optional,
   },
diff --git a/k9-svc/register.ncl b/k9-svc/register.ncl
index d9788abb..81b7ee78 100644
--- a/k9-svc/register.ncl
+++ b/k9-svc/register.ncl
@@ -12,7 +12,7 @@ let OS = [| 'Linux, 'Minix, 'MacOS |] in
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- SPDX-License-Identifier: MPL-2.0 -->
 <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
-  <mime-type type="application/vnd.k9+nickel">
+  <mime-type type="application/vnd.k9">
     <comment>K9 Self-Validating Component</comment>
     <comment xml:lang="en">K9 Self-Validating Component (Alpha Breed)</comment>
     <magic priority="50">
@@ -51,7 +51,7 @@ let OS = [| 'Linux, 'Minix, 'MacOS |] in
           <string>k9.ncl</string>
         </array>
         <key>public.mime-type</key>
-        <string>application/vnd.k9+nickel</string>
+        <string>application/vnd.k9</string>
       </dict>
     </dict>
   </array>
@@ -97,7 +97,7 @@ User-only:
 
 Verification:
   file --mime-type example.k9
-  # Should output: application/vnd.k9+nickel
+  # Should output: application/vnd.k9
 
 Manual registration:
   Linux: Copy k9.xml to /usr/share/mime/packages/ then run update-mime-database