added v71 release highlights and date update (#458)

Author: theekrystallee

hedera/networks/release-notes/services.mdx

@@ -7,11 +7,28 @@ Visit the [Hedera status page](https://status.hedera.com/) for the latest versio
 
 ## Release v0.71
 <Info>
-  **MAINNET UPDATE: MARCH 11, 2026**
+  **MAINNET UPDATE: MARCH 18, 2026**
 </Info>
 
+## Release highlights
+
+Release 0.71 focuses on strengthening core infrastructure and expanding observability to support downstream services and future network capabilities.
+
+<Accordion title="What's new in Release v0.71?">
+  **TSS Infrastructure Improvements**
+  Enhancements to signature set handling improve reliability during reconnect scenarios.
+
+  **State Metrics API Expansion**
+  Additional State Metrics API methods have been implemented to support BlockNode, enabling downstream services to access additional node state information required for block production and analytics workflows.
+
+</Accordion>
+
 ### [**Build 0.71.3**](https://github.com/hiero-ledger/hiero-consensus-node/releases/tag/v0.71.3)
 
+<Check>
+  **TESTNET UPDATED: MARCH 10, 2026**
+</Check>
+
 <Accordion title="What's Changed">
 Bug Fixes
   * add hiero logger #23649 #23709 by @mxtartaglia-sl