diff --git a/js/sign/README.md b/js/sign/README.md
index 325f849e..3da28ecb 100644
--- a/js/sign/README.md
+++ b/js/sign/README.md
@@ -194,6 +194,13 @@ environment variable named `WEB_BUNDLE_SIGNING_PASSPHRASE`.
 
 ## Release Notes
 
+### v0.2.1
+
+- Moved is_v2 to the last and optional (defaulting to true) argument of
+  `IntegrityBlockSigner` constructor. This is a preparation for the future
+  removal of the deprecated v1 format.
+- CLI signer defaults to v2 format of integrity block now.
+
 ### v0.2.0
 
 - Add support for the v2 integrity block format. Now web-bundle-id is no longer
diff --git a/js/sign/package.json b/js/sign/package.json
index 71550f5d..5ae0feaa 100644
--- a/js/sign/package.json
+++ b/js/sign/package.json
@@ -1,6 +1,6 @@
 {
   "name": "wbn-sign",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Signing tool to sign a web bundle with integrity block",
   "homepage": "https://github.com/WICG/webpackage/tree/main/js/sign",
   "main": "./lib/wbn-sign.cjs",
@@ -34,7 +34,8 @@
   "author": "Sonja Laurila <laurila@google.com> (https://github.com/sonkkeli)",
   "contributors": [
     "Christian Flach <cmfcmf@google.com> (https://github.com/cmfcmf)",
-    "Andrew Rayskiy <greengrape@google.com> (https://github.com/GrapeGreen)"
+    "Andrew Rayskiy <greengrape@google.com> (https://github.com/GrapeGreen)",
+    "Luke (Zgroza) Klimek <zgroza@google.com> (https://github.com/zgroza)"
   ],
   "license": "W3C-20150513",
   "dependencies": {
diff --git a/js/sign/src/cli-sign.ts b/js/sign/src/cli-sign.ts
index a47e06dc..8c06b8e2 100644
--- a/js/sign/src/cli-sign.ts
+++ b/js/sign/src/cli-sign.ts
@@ -20,7 +20,7 @@ const program = new Command()
 function readOptions() {
   return program
     .addOption(
-      new Option('--version <version>').choices(['v1', 'v2']).default('v1')
+      new Option('--version <version>').choices(['v1', 'v2']).default('v2')
     )
     .requiredOption(
       '-i, --input <file>',
@@ -80,10 +80,10 @@ export async function main() {
     ? options.webBundleId
     : new WebBundleId(privateKeys[0]).serialize();
   const signer = new IntegrityBlockSigner(
-    /*is_v2=*/ options.version === 'v2',
     webBundle,
     webBundleId,
-    privateKeys.map((privateKey) => new NodeCryptoSigningStrategy(privateKey))
+    privateKeys.map((privateKey) => new NodeCryptoSigningStrategy(privateKey)),
+    /*is_v2=*/ options.version === 'v2'
   );
   const { signedWebBundle } = await signer.sign();
   greenConsoleLog(`${webBundleId}`);
diff --git a/js/sign/src/signers/integrity-block-signer.ts b/js/sign/src/signers/integrity-block-signer.ts
index 917b9524..55e95cb6 100644
--- a/js/sign/src/signers/integrity-block-signer.ts
+++ b/js/sign/src/signers/integrity-block-signer.ts
@@ -24,10 +24,10 @@ type IntegritySignature = {
 export class IntegrityBlockSigner {
   // `webBundleId` is ignored if `is_v2` is false.
   constructor(
-    private readonly is_v2: boolean,
     private readonly webBundle: Uint8Array,
     private readonly webBundleId: string,
-    private readonly signingStrategies: Array<ISigningStrategy>
+    private readonly signingStrategies: Array<ISigningStrategy>,
+    private readonly is_v2: boolean = true
   ) {}
 
   async sign(): Promise<{
diff --git a/js/sign/tests/integrity-block-signer_test.js b/js/sign/tests/integrity-block-signer_test.js
index 91ff13dc..8e030431 100644
--- a/js/sign/tests/integrity-block-signer_test.js
+++ b/js/sign/tests/integrity-block-signer_test.js
@@ -65,12 +65,12 @@ describe('Integrity Block Signer', () => {
     const file = path.resolve(__dirname, 'testdata/unsigned.wbn');
     const contents = fs.readFileSync(file);
     const signer = new wbnSign.IntegrityBlockSigner(
-      /*is_v2=*/ !!webBundleId,
       contents,
       /*webBundleId=*/ webBundleId,
       privateKeys.map(
         (privateKey) => new wbnSign.NodeCryptoSigningStrategy(privateKey)
-      )
+      ),
+      /*is_v2=*/ !!webBundleId
     );
     return signer;
   }