Use context package named Map for context URLs.

lib/helpers.js

@@ -1,6 +1,8 @@
 /*!
  * Copyright (c) 2023 Digital Bazaar, Inc. All rights reserved.
  */
+import {named as vcNamedContexts} from '@digitalbazaar/credentials-context';
+
 // Z and T must be uppercase
 // xml schema date time RegExp
 // @see https://www.w3.org/TR/xmlschema11-2/#dateTime
@@ -11,8 +13,8 @@ export const dateRegex = new RegExp(
   'T(([01][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9](\.[0-9]+)?|(24:00:00(\.0+)?))' +
   '(Z|(\\+|-)((0[0-9]|1[0-3]):[0-5][0-9]|14:00))?');
 
-const CREDENTIALS_CONTEXT_V1_URL = 'https://www.w3.org/2018/credentials/v1';
-const CREDENTIALS_CONTEXT_V2_URL = 'https://www.w3.org/ns/credentials/v2';
+const CREDENTIALS_CONTEXT_V1_URL = vcNamedContexts.get('v1').id;
+const CREDENTIALS_CONTEXT_V2_URL = vcNamedContexts.get('v2').id;
 
 // mappings between credentials contexts and version numbers
 const credentialsContextUrlToVersion = new Map([

package.json

@@ -28,7 +28,7 @@
     "lib/**/*.js"
   ],
   "dependencies": {
-    "@digitalbazaar/credentials-context": "^3.0.0",
+    "@digitalbazaar/credentials-context": "^3.1.0",
     "ed25519-signature-2018-context": "^1.1.0",
     "jsonld": "^8.3.1",
     "jsonld-signatures": "^11.2.1"