diff --git a/package-lock.json b/package-lock.json
index 8d5db3bab..1cecafafb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2469,6 +2469,49 @@
         "node": ">=10.0.0"
       }
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+    "node_modules/@web/dev-server-core/node_modules/koa": {
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+      "resolved": "https://registry.npmjs.org/koa/-/koa-2.16.1.tgz",
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+      "license": "MIT",
+      "dependencies": {
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+        "cache-content-type": "^1.0.0",
+        "content-disposition": "~0.5.2",
+        "content-type": "^1.0.4",
+        "cookies": "~0.9.0",
+        "debug": "^4.3.2",
+        "delegates": "^1.0.0",
+        "depd": "^2.0.0",
+        "destroy": "^1.0.4",
+        "encodeurl": "^1.0.2",
+        "escape-html": "^1.0.3",
+        "fresh": "~0.5.2",
+        "http-assert": "^1.3.0",
+        "http-errors": "^1.6.3",
+        "is-generator-function": "^1.0.7",
+        "koa-compose": "^4.1.0",
+        "koa-convert": "^2.0.0",
+        "on-finished": "^2.3.0",
+        "only": "~0.0.2",
+        "parseurl": "^1.3.2",
+        "statuses": "^1.5.0",
+        "type-is": "^1.6.16",
+        "vary": "^1.1.2"
+      },
+      "engines": {
+        "node": "^4.8.4 || ^6.10.1 || ^7.10.1 || >= 8.1.4"
+      }
+    },
+    "node_modules/@web/dev-server-core/node_modules/statuses": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/statuses/-/statuses-1.5.0.tgz",
+      "integrity": "sha512-OpZ3zP+jT1PI7I8nemJX4AKmAX070ZkYPVWV/AaKTJl+tXCTGyVdC1a4SL8RUQYEwk/f34ZX8UTykN68FwrqAA==",
+      "license": "MIT",
+      "engines": {
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+      }
+    },
     "node_modules/@web/dev-server-rollup": {
       "version": "0.3.17",
       "license": "MIT",
@@ -3101,6 +3144,8 @@
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       "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/cache-content-type/-/cache-content-type-1.0.1.tgz",
+      "integrity": "sha512-IKufZ1o4Ut42YUrZSo8+qnMTrFuKkvyoLXUywKz9GJ5BrhOFGhLdkx9sG4KAnVvbY6kEcSFjLQul+DVmBm2bgA==",
       "license": "MIT",
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@@ -3319,6 +3364,8 @@
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       "version": "4.6.0",
+      "resolved": "https://registry.npmjs.org/co/-/co-4.6.0.tgz",
+      "integrity": "sha512-QVb0dM5HvG+uaxitm8wONl7jltx8dqhfU33DcqtOZcLSVIKSDDLDi7+0LbAKiyI8hD9u42m2YxXSkMGWThaecQ==",
       "license": "MIT",
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@@ -3505,14 +3552,18 @@
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     "node_modules/content-type": {
-      "version": "1.0.4",
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/content-type/-/content-type-1.0.5.tgz",
+      "integrity": "sha512-nTjqfcBFEipKdXCv4YDQWCfmcLZKm81ldF0pAopTvyrFGVbcR6P/VAAd5G7N+0tTr8QqiU0tFadD6FK4NtJwOA==",
       "license": "MIT",
       "engines": {
         "node": ">= 0.6"
       }
     },
     "node_modules/cookies": {
-      "version": "0.8.0",
+      "version": "0.9.1",
+      "resolved": "https://registry.npmjs.org/cookies/-/cookies-0.9.1.tgz",
+      "integrity": "sha512-TG2hpqe4ELx54QER/S3HQ9SRVnQnGBtKUz5bLQWtYAQ+o6GpgMs6sYUvaiJjVxb+UXwhRhAEP3m7LbsIZ77Hmw==",
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@@ -5716,6 +5767,8 @@
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     "node_modules/keygrip": {
       "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/keygrip/-/keygrip-1.1.0.tgz",
+      "integrity": "sha512-iYSchDJ+liQ8iwbSI2QqsQOvqv58eJCEanyJPJi+Khyu8smkcKSFUCbPwzFcL7YVtZ6eONjqRX/38caJ7QjRAQ==",
       "license": "MIT",
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@@ -5740,39 +5793,38 @@
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     "node_modules/koa": {
-      "version": "2.13.4",
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/koa/-/koa-3.0.1.tgz",
+      "integrity": "sha512-oDxVkRwPOHhGlxKIDiDB2h+/l05QPtefD7nSqRgDfZt8P+QVYFWjfeK8jANf5O2YXjk8egd7KntvXKYx82wOag==",
       "license": "MIT",
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-        "cache-content-type": "^1.0.0",
-        "content-disposition": "~0.5.2",
-        "content-type": "^1.0.4",
-        "cookies": "~0.8.0",
-        "debug": "^4.3.2",
+        "accepts": "^1.3.8",
+        "content-disposition": "~0.5.4",
+        "content-type": "^1.0.5",
+        "cookies": "~0.9.1",
         "delegates": "^1.0.0",
-        "depd": "^2.0.0",
-        "destroy": "^1.0.4",
-        "encodeurl": "^1.0.2",
+        "destroy": "^1.2.0",
+        "encodeurl": "^2.0.0",
         "escape-html": "^1.0.3",
         "fresh": "~0.5.2",
-        "http-assert": "^1.3.0",
-        "http-errors": "^1.6.3",
-        "is-generator-function": "^1.0.7",
+        "http-assert": "^1.5.0",
+        "http-errors": "^2.0.0",
         "koa-compose": "^4.1.0",
-        "koa-convert": "^2.0.0",
-        "on-finished": "^2.3.0",
-        "only": "~0.0.2",
-        "parseurl": "^1.3.2",
-        "statuses": "^1.5.0",
-        "type-is": "^1.6.16",
+        "mime-types": "^3.0.1",
+        "on-finished": "^2.4.1",
+        "parseurl": "^1.3.3",
+        "statuses": "^2.0.1",
+        "type-is": "^2.0.1",
         "vary": "^1.1.2"
       },
       "engines": {
-        "node": "^4.8.4 || ^6.10.1 || ^7.10.1 || >= 8.1.4"
+        "node": ">= 18"
       }
     },
     "node_modules/koa-compose": {
       "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/koa-compose/-/koa-compose-4.1.0.tgz",
+      "integrity": "sha512-8ODW8TrDuMYvXRwra/Kh7/rJo9BtOfPc6qO8eAfC80CnCvSjSl0bkRM24X6/XBBEyj0v1nRUQ1LyOy3dbqOWXw==",
       "license": "MIT"
     },
     "node_modules/koa-conditional-get": {
@@ -5781,6 +5833,8 @@
     },
     "node_modules/koa-convert": {
       "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/koa-convert/-/koa-convert-2.0.0.tgz",
+      "integrity": "sha512-asOvN6bFlSnxewce2e/DK3p4tltyfC4VM7ZwuTuepI7dEQVcvpyFuBcEARu1+Hxg8DIwytce2n7jrZtRlPrARA==",
       "license": "MIT",
       "dependencies": {
         "co": "^4.6.0",
@@ -5827,9 +5881,71 @@
         "ms": "^2.1.1"
       }
     },
-    "node_modules/koa/node_modules/statuses": {
-      "version": "1.5.0",
+    "node_modules/koa/node_modules/encodeurl": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/encodeurl/-/encodeurl-2.0.0.tgz",
+      "integrity": "sha512-Q0n9HRi4m6JuGIV1eFlmvJB7ZEVxu93IrMyiMsGC0lrMJMWzRgx6WGquyfQgZVb31vhGgXnfmPNNXmxnOkRBrg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/koa/node_modules/http-errors": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/http-errors/-/http-errors-2.0.0.tgz",
+      "integrity": "sha512-FtwrG/euBzaEjYeRqOgly7G0qviiXoJWnvEH2Z1plBdXgbyjv34pHTSb9zoeHMyDy33+DWy5Wt9Wo+TURtOYSQ==",
+      "license": "MIT",
+      "dependencies": {
+        "depd": "2.0.0",
+        "inherits": "2.0.4",
+        "setprototypeof": "1.2.0",
+        "statuses": "2.0.1",
+        "toidentifier": "1.0.1"
+      },
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/koa/node_modules/media-typer": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/media-typer/-/media-typer-1.1.0.tgz",
+      "integrity": "sha512-aisnrDP4GNe06UcKFnV5bfMNPBUw4jsLGaWwWfnH3v02GnBuXX2MCVn5RbrWo0j3pczUilYblq7fQ7Nw2t5XKw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/koa/node_modules/mime-db": {
+      "version": "1.54.0",
+      "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.54.0.tgz",
+      "integrity": "sha512-aU5EJuIN2WDemCcAp2vFBfp/m4EAhWJnUNSSw0ixs7/kXbd6Pg64EmwJkNdFhB8aWt1sH2CTXrLxo/iAGV3oPQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
+    "node_modules/koa/node_modules/mime-types": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-3.0.1.tgz",
+      "integrity": "sha512-xRc4oEhT6eaBpU1XF7AjpOFD+xQmXNB5OVKwp4tqCuBpHLS/ZbBDrc07mYTDqVMg6PfxUjjNp85O6Cd2Z/5HWA==",
       "license": "MIT",
+      "dependencies": {
+        "mime-db": "^1.54.0"
+      },
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
+    "node_modules/koa/node_modules/type-is": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/type-is/-/type-is-2.0.1.tgz",
+      "integrity": "sha512-OZs6gsjF4vMp32qrCbiVSkrFmXtG/AZhY3t0iAMrMBiAZyV9oALtXO8hsrHbMXF9x6L3grlFuwW2oAz7cav+Gw==",
+      "license": "MIT",
+      "dependencies": {
+        "content-type": "^1.0.5",
+        "media-typer": "^1.1.0",
+        "mime-types": "^3.0.0"
+      },
       "engines": {
         "node": ">= 0.6"
       }
@@ -6581,7 +6697,9 @@
       }
     },
     "node_modules/only": {
-      "version": "0.0.2"
+      "version": "0.0.2",
+      "resolved": "https://registry.npmjs.org/only/-/only-0.0.2.tgz",
+      "integrity": "sha512-Fvw+Jemq5fjjyWz6CpKx6w9s7xxqo3+JCyM0WXWeCSOboZ8ABkyvP8ID4CZuChA/wxSx+XSJmdOm8rGVyJ1hdQ=="
     },
     "node_modules/open": {
       "version": "8.4.0",
@@ -8106,6 +8224,8 @@
     },
     "node_modules/tsscmp": {
       "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/tsscmp/-/tsscmp-1.0.6.tgz",
+      "integrity": "sha512-LxhtAkPDTkVCMQjt2h6eBVY28KCjikZqZfMcC15YBeNjkgUpdCfBu5HoiOTDu86v6smE8yOjyEktJ8hlbANHQA==",
       "license": "MIT",
       "engines": {
         "node": ">=0.6.x"
@@ -8670,7 +8790,9 @@
       "license": "ISC"
     },
     "node_modules/ylru": {
-      "version": "1.3.2",
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/ylru/-/ylru-1.4.0.tgz",
+      "integrity": "sha512-2OQsPNEmBCvXuFlIni/a+Rn+R2pHW9INm0BxXJ4hVDA8TirqMj+J/Rp9ItLatT/5pZqWwefVrTQcHpixsxnVlA==",
       "license": "MIT",
       "engines": {
         "node": ">= 4.0.0"
@@ -8918,7 +9040,7 @@
       "version": "0.0.0",
       "license": "BSD-3-Clause",
       "dependencies": {
-        "koa": "^2.13.0",
+        "koa": "^3.0.1",
         "koa-conditional-get": "^3.0.0",
         "koa-etag": "^4.0.0",
         "koa-send": "^5.0.0",
diff --git a/packages/lit-dev-server/package.json b/packages/lit-dev-server/package.json
index 850623d82..17ff49dff 100644
--- a/packages/lit-dev-server/package.json
+++ b/packages/lit-dev-server/package.json
@@ -61,7 +61,7 @@
     }
   },
   "dependencies": {
-    "koa": "^2.13.0",
+    "koa": "^3.0.1",
     "koa-conditional-get": "^3.0.0",
     "koa-etag": "^4.0.0",
     "koa-send": "^5.0.0",