diff --git a/CHANGELOG.md b/CHANGELOG.md
index 081639f..4f5d4bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.4.0
+
+- fix exec function
+- replace diff with structural diff
+- add package '@types/jsonpath'
+
 ## 0.3.9
 
 - remove global variables
diff --git a/package.json b/package.json
index 9e8cb85..be5abd0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@azure/rest-api-specs-scripts",
-  "version": "0.3.9",
+  "version": "0.4.0",
   "description": "Scripts for the Azure RestAPI specification repository 'azure-rest-api-specs'.",
   "types": "dist/index.d.ts",
   "main": "dist/index.js",
@@ -27,6 +27,7 @@
     "@types/fs-extra": "^5.0.5",
     "@types/glob": "^7.1.1",
     "@types/js-yaml": "^3.12.1",
+    "@types/jsonpath": "^0.2.0",
     "@types/node": "^11.13.6",
     "@types/request": "^2.48.1",
     "typescript": "^3.4.4"
diff --git a/src/modelValidation.ts b/src/modelValidation.ts
index 3addda0..831c7ba 100644
--- a/src/modelValidation.ts
+++ b/src/modelValidation.ts
@@ -20,14 +20,14 @@ const exec = (cmd: string, options?: cp.SpawnSyncOptions) => {
 export async function main() {
   const pr = await devOps.createPullRequestProperties(cli.defaultConfig())
   const swaggersToProcess = await utils.getFilesChangedInPR(pr);
-  let result = 0
+  let result: number = 0
   for (const swagger of swaggersToProcess) {
     try {
       // await oav.validateExamples(swagger, null, {consoleLogLevel: 'error', pretty: true});
       // run OAV as a separate process to avoid memory issues.
       const r = exec(`node node_modules/oav/dist/cli.js validate-example ${swagger} --pretty`)
       if (result === 0) {
-        result = r
+        result = r === null ? 1 : r
       }
     } catch (e) {
       console.error("error: ")
diff --git a/src/utils.ts b/src/utils.ts
index ef7bccf..3a60da2 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -236,7 +236,7 @@ export const getConfigFilesChangedInPR = async (pr: devOps.PullRequestProperties
       console.log(filesChanged);
 
       // traverse up to readme.md files
-      const configFiles = new Set();
+      const configFiles = new Set<string>();
       for (let fileChanged of filesChanged) {
         while (fileChanged.startsWith("specification")) {
           if (fileChanged.toLowerCase().endsWith("readme.md") && fs.existsSync(fileChanged)) {
@@ -273,7 +273,7 @@ export const getFilesChangedInPR = async (pr: devOps.PullRequestProperties | und
   let result = getSwaggers();
   if (pr !== undefined) {
     try {
-      let filesChanged = (await pr.diff()).map(file => file.path)
+      let filesChanged = (await pr.structuralDiff().toArray())
       console.log('>>>>> Files changed in this PR are as follows:')
       console.log(filesChanged);
       let swaggerFilesInPR = filesChanged.filter(function (item: string) {