diff --git a/.github/workflows/ts-tests.yml b/.github/workflows/ts-tests.yml
index 79d2e895d3..5e110e9253 100644
--- a/.github/workflows/ts-tests.yml
+++ b/.github/workflows/ts-tests.yml
@@ -24,9 +24,9 @@ jobs:
       - name: Prepare build environment
         uses: ./.github/actions/prepare-build-env
       - name: Setup Node.js environment
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
-          node-version: 18
+          node-version: 22
       - name: Install pnpm
         run: npm i -g pnpm
       - name: Install coreutils (macOS)
diff --git a/core/src/main/java/org/lflang/util/ImportUtil.java b/core/src/main/java/org/lflang/util/ImportUtil.java
index b7de0a16d4..432f70574b 100644
--- a/core/src/main/java/org/lflang/util/ImportUtil.java
+++ b/core/src/main/java/org/lflang/util/ImportUtil.java
@@ -25,8 +25,8 @@ public class ImportUtil {
    *     names.
    */
   public static String buildPackageURI(String uriStr, Resource resource) {
-    Path rootPath = Paths.get(resource.getURI().toString()).toAbsolutePath();
 
+    Path rootPath = FileUtil.toPath(resource);
     Path uriPath = Paths.get(uriStr.trim());
 
     if (uriPath.getNameCount() < 2) {
diff --git a/core/src/main/resources/lib/ts/package.json b/core/src/main/resources/lib/ts/package.json
index fc063d791e..eec471ab6d 100644
--- a/core/src/main/resources/lib/ts/package.json
+++ b/core/src/main/resources/lib/ts/package.json
@@ -2,7 +2,7 @@
     "name": "LinguaFrancaDefault",
     "type": "commonjs",
     "dependencies": {
-        "@lf-lang/reactor-ts": "git://github.com/lf-lang/reactor-ts.git#master",
+        "@lf-lang/reactor-ts": "^0.6.1",
         "command-line-args": "^5.1.1",
         "command-line-usage": "^6.1.3"
     },
@@ -11,13 +11,12 @@
         "@types/command-line-usage": "^5.0.2",
         "@types/google-protobuf": "^3.7.4",
         "@types/microtime": "^2.1.0",
-        "@types/node": "^18.14.2",
-        "@typescript-eslint/eslint-plugin": "5.33.0",
-        "@typescript-eslint/parser": "^5.8.1",
-        "eslint": "^8.5.0",
-        "typescript": "~4.8.2",
+        "@types/node": "^22.5.0",
+        "eslint-config-prettier": "^9.0.0",
+        "eslint-config-standard-with-typescript": "^43.0.1",
+        "typescript": "^5.1.6",
         "ts-protoc-gen": "^0.15.0",
-        "rimraf": "^3.0.2"
+        "rimraf": "^6.0.1"
     },
     "scripts": {
         "build": "npx rimraf dist && npx tsc --outDir dist"
diff --git a/core/src/main/resources/lib/ts/tsconfig.json b/core/src/main/resources/lib/ts/tsconfig.json
index ae7bb7804a..bd1f323b67 100644
--- a/core/src/main/resources/lib/ts/tsconfig.json
+++ b/core/src/main/resources/lib/ts/tsconfig.json
@@ -4,7 +4,6 @@
         "target": "esnext",
         "module": "CommonJS",
         "types": ["node", "@lf-lang/reactor-ts", "microtime", "command-line-args", "command-line-usage"],
-        "typeRoots": ["./node_modules/@types/", "./node_modules/@lf-lang/reactor-ts/src/core/@types/"],
         "esModuleInterop": true,
         "isolatedModules": true,
         "lib": ["esnext", "dom"],
diff --git a/test/C/src/Mutable.lf b/test/C/src/Mutable.lf
index 575473986f..220ff1afbd 100644
--- a/test/C/src/Mutable.lf
+++ b/test/C/src/Mutable.lf
@@ -11,7 +11,9 @@ reactor S(width: int = 4) {
 }
 
 reactor R(width: int = 4) {
-  mutable input[width] in: int
+  // Pathetically, the Windows C compiler doesn't support arrays on the stack with a variable size.
+  // So we have to give a constant here instead of the parameter width.
+  mutable input[2] in: int
   output[width] out: int
 
   reaction(in) -> out {=
diff --git a/test/C/src/token/MutableToken.lf b/test/C/src/token/MutableToken.lf
index 724b8a6579..33d86be4b0 100644
--- a/test/C/src/token/MutableToken.lf
+++ b/test/C/src/token/MutableToken.lf
@@ -10,7 +10,9 @@ preamble {=
 =}
 
 reactor R(width: int = 4) {
-  mutable input[width] in: int_array_t*
+  // Pathetically, the Windows C compiler doesn't support arrays on the stack with a variable size.
+  // So we have to give a constant here instead of the parameter width.
+  mutable input[2] in: int_array_t*
   output[width] out: int_array_t*
 
   reaction(in) -> out {=
diff --git a/test/Python/src/LingoFederatedImport.lf b/test/Python/src/federated/LingoFederatedImport.lf
similarity index 89%
rename from test/Python/src/LingoFederatedImport.lf
rename to test/Python/src/federated/LingoFederatedImport.lf
index 5b3a4fadd6..6c642bae6f 100644
--- a/test/Python/src/LingoFederatedImport.lf
+++ b/test/Python/src/federated/LingoFederatedImport.lf
@@ -1,5 +1,4 @@
 # Test the new import statement for Lingo downloaded packages with the import path enclosed in angle brackets
-# Version 1: The LF file is located in "src".
 target Python {
   timeout: 2 sec
 }
diff --git a/test/Python/src/lingo_imports/FederatedTestImportPackages.lf b/test/Python/src/lingo_imports/FederatedTestImportPackages.lf
deleted file mode 100644
index 4081aa29ba..0000000000
--- a/test/Python/src/lingo_imports/FederatedTestImportPackages.lf
+++ /dev/null
@@ -1,21 +0,0 @@
-# Test the new import statement for Lingo downloaded packages with the import path enclosed in angle brackets
-# Version 2: The LF file is now located in a subdirectory under "src".
-target Python {
-  timeout: 2 sec
-}
-
-import Count from <library-test/Import.lf>
-
-reactor Actuator {
-  input results
-
-  reaction(results) {=
-    print(f"Count: {results.value}")
-  =}
-}
-
-federated reactor {
-  count = new Count()
-  act = new Actuator()
-  count.out -> act.results
-}