diff --git a/src/__tests__/networks.integration.test.ts b/src/__tests__/networks.integration.test.ts
index 1ca3b1fe..a34dcb83 100644
--- a/src/__tests__/networks.integration.test.ts
+++ b/src/__tests__/networks.integration.test.ts
@@ -16,7 +16,7 @@ describe('ethrResolver (alt-chains)', () => {
       expect(result).toEqual({
         didDocumentMetadata: {
           nextVersionId: '12090175',
-          nextUpdate: '2021-03-22T18:14:29.000Z',
+          nextUpdate: '2021-03-22T18:14:29Z',
         },
         didResolutionMetadata: {
           contentType: 'application/did+ld+json',
diff --git a/src/resolver.ts b/src/resolver.ts
index 0c25e7e9..6f07e8f2 100644
--- a/src/resolver.ts
+++ b/src/resolver.ts
@@ -68,7 +68,7 @@ export class EthrDidResolver {
     const block: Block = await this.contracts[networkId].provider.getBlock(blockHeight)
     return {
       height: block.number.toString(),
-      isoDate: new Date(block.timestamp * 1000).toISOString(),
+      isoDate: new Date(block.timestamp * 1000).toISOString().replace('.000', ''),
     }
   }