diff --git a/core/src/main/java/org/kohsuke/stapler/Stapler.java b/core/src/main/java/org/kohsuke/stapler/Stapler.java
index a63bd9862..5cd869a1c 100644
--- a/core/src/main/java/org/kohsuke/stapler/Stapler.java
+++ b/core/src/main/java/org/kohsuke/stapler/Stapler.java
@@ -675,11 +675,7 @@ private String getMimeType(String fileName) {
         idx = fileName.lastIndexOf('\\');
         fileName = fileName.substring(idx + 1);
 
-        String extension = fileName.substring(fileName.lastIndexOf('.') + 1);
-        String mimeType = webApp.mimeTypes.get(extension);
-        if (mimeType == null) {
-            mimeType = getServletContext().getMimeType(fileName);
-        }
+        String mimeType = getServletContext().getMimeType(fileName);
         if (mimeType == null) {
             mimeType = "application/octet-stream";
         }
diff --git a/core/src/main/java/org/kohsuke/stapler/WebApp.java b/core/src/main/java/org/kohsuke/stapler/WebApp.java
index 3525bada8..75a48d29e 100644
--- a/core/src/main/java/org/kohsuke/stapler/WebApp.java
+++ b/core/src/main/java/org/kohsuke/stapler/WebApp.java
@@ -111,7 +111,10 @@ public static WebApp get(ServletContext context) {
      *
      * This overrides whatever mappings given in the servlet as far as stapler is concerned.
      * This is case insensitive, and should be normalized to lower case.
+     *
+     * @deprecated removed without replacement
      */
+    @Deprecated
     public final Map<String, String> mimeTypes = new Hashtable<>();
 
     private volatile ClassLoader classLoader;