diff --git a/src/node/utils/Minify.js b/src/node/utils/Minify.js
index 4874432b1..dc31895a4 100644
--- a/src/node/utils/Minify.js
+++ b/src/node/utils/Minify.js
@@ -146,6 +146,14 @@ const minify = async (req, res) => {
     filename = 'js/vendors/jquery.js';
   }
 
+  // Backward compatibility for plugins that were written when underscore lived at
+  // src/static/js/underscore.js.
+  if (['js/underscore.js', 'plugins/ep_etherpad-lite/static/js/underscore.js']
+      .indexOf(filename) !== -1) {
+    logger.warn(`request for deprecated underscore path: ${filename}`);
+    filename = 'js/vendors/underscore.js';
+  }
+
   /* Handle static files for plugins/libraries:
      paths like "plugins/ep_myplugin/static/js/test.js"
      are rewritten into ROOT_PATH_OF_MYPLUGIN/static/js/test.js,
diff --git a/src/node/utils/tar.json b/src/node/utils/tar.json
index 04ac8604e..ad85664ae 100644
--- a/src/node/utils/tar.json
+++ b/src/node/utils/tar.json
@@ -83,4 +83,5 @@
   , "pluginfw/hooks.js"
   ]
 , "jquery.js": ["jquery.js"]
+, "underscore.js": ["underscore.js"]
 }