diff --git a/README.md b/README.md
index fc178e540..1e9050155 100644
--- a/README.md
+++ b/README.md
@@ -11,13 +11,13 @@ This repository, heraj is java implementation for hera.
 
 ## Lastest
 
-v0.10.0
+v0.11.0
 
-build with aergo-protobuf v0.10.0
+build with aergo-protobuf v0.11.0
 
 ## Compatibility
 
-* Aergo : v0.10.x
+* Aergo : v0.11.x
 * Java : JDK 6 or higher
 * Android : Android 3.0 (API 11) or higher
 
@@ -47,17 +47,17 @@ If you just want a minimum one, use `heraj-transport`. Or need more feature, use
   <dependency>
     <groupId>io.aergo</groupId>
     <artifactId>heraj-transport</artifactId>
-    <version>0.10.0</version>
+    <version>0.11.0</version>
   </dependency>
   <dependency>
     <groupId>io.aergo</groupId>
     <artifactId>heraj-wallet</artifactId>
-    <version>0.10.0</version>
+    <version>0.11.0</version>
   </dependency>
   <dependency>
     <groupId>io.aergo</groupId>
     <artifactId>heraj-smart-contract</artifactId>
-    <version>0.10.0</version>
+    <version>0.11.0</version>
   </dependency>
 </dependencies>
 ```
@@ -72,9 +72,9 @@ repositories {
 ...
 
 dependencies {
-  implementation 'io.aergo:heraj-transport:0.10.0'
-  implementation 'io.aergo:heraj-wallet:0.10.0'
-  implementation 'io.aergo:heraj-smart-contract:0.10.0'
+  implementation 'io.aergo:heraj-transport:0.11.0'
+  implementation 'io.aergo:heraj-wallet:0.11.0'
+  implementation 'io.aergo:heraj-smart-contract:0.11.0'
 }
 ```
 
diff --git a/examples/src/main/java/hera/example/highlevel/BlockLookup.java b/examples/src/main/java/hera/example/highlevel/BlockLookup.java
index 47bd9e48a..1016e2653 100644
--- a/examples/src/main/java/hera/example/highlevel/BlockLookup.java
+++ b/examples/src/main/java/hera/example/highlevel/BlockLookup.java
@@ -26,15 +26,15 @@ protected void blockLookup() {
     final BlockHash bestHash = wallet.getBestBlockHash();
     final long bestHeight = wallet.getBestBlockHeight();
 
-    // lookup block by best block hash
+    // query block by best block hash
     final Block blockByHash = wallet.getBlock(bestHash);
     System.out.println("Block by hash: " + blockByHash);
 
-    // lookup block by best height
+    // query block by best height
     final Block blockByHeight = wallet.getBlock(bestHeight);
     System.out.println("Block by height: " + blockByHeight);
 
-    // lookup previous block by hash
+    // query previous block by hash
     final Block previousBlock =
         wallet.getBlock(blockByHash.getPreviousHash());
     System.out.println("Previous block: " + previousBlock);
@@ -52,16 +52,24 @@ protected void blockHeaderLookup() {
 
     // get best block hash, height
     final BlockHash bestHash = wallet.getBestBlockHash();
-    final Block block = wallet.getBlock(bestHash);
+    final long bestHeight = wallet.getBestBlockHeight();
+
+    // query block header corresponding to the block hash
+    final BlockHeader blockHeaderByHash = wallet.getBlockHeader(bestHash);
+    System.out.println("Block header by hash: " + blockHeaderByHash);
+
+    // query block header corresponding to the block hash
+    final BlockHeader blockHeaderByHeight = wallet.getBlockHeader(bestHeight);
+    System.out.println("Block header by height: " + blockHeaderByHeight);
 
-    // lookup 10 block headers starting from best block backward with best block hash
+    // query 10 block headers starting from best block backward with best block hash
     final List<BlockHeader> blockHeadersByHash =
-        wallet.listBlockHeaders(block.getHash(), 10);
+        wallet.listBlockHeaders(bestHash, 10);
     System.out.println("Block headers by hash: " + blockHeadersByHash);
 
-    // lookup 10 block headers starting from best block backward with best block height
+    // query 10 block headers starting from best block backward with best block height
     final List<BlockHeader> blockHeadersByHeight =
-        wallet.listBlockHeaders(block.getBlockNumber(), 10);
+        wallet.listBlockHeaders(bestHeight, 10);
     System.out.println("Block headers by height: " + blockHeadersByHeight);
 
     // close the client
diff --git a/examples/src/main/java/hera/example/highlevel/SendAergo.java b/examples/src/main/java/hera/example/highlevel/SendAergo.java
index c66991a69..5d408e787 100644
--- a/examples/src/main/java/hera/example/highlevel/SendAergo.java
+++ b/examples/src/main/java/hera/example/highlevel/SendAergo.java
@@ -69,11 +69,12 @@ protected void sendAergoWithSecure() throws Exception {
         .withNonBlockingConnect()
         .build(WalletType.Secure);
 
-    // bind keystore
-    final KeyStore keyStore = KeyStore.getInstance("JKS");
     // here, make a new keystore
     // if exists, load with input stream and password
+    final KeyStore keyStore = KeyStore.getInstance("JKS");
     keyStore.load(null, null);
+
+    // bind keystore
     wallet.bindKeyStore(keyStore);
 
     // create an account
diff --git a/examples/src/main/java/hera/example/lowlevel/BlockLookup.java b/examples/src/main/java/hera/example/lowlevel/BlockLookup.java
index 510944f16..aef182e1f 100644
--- a/examples/src/main/java/hera/example/lowlevel/BlockLookup.java
+++ b/examples/src/main/java/hera/example/lowlevel/BlockLookup.java
@@ -5,6 +5,7 @@
 package hera.example.lowlevel;
 
 import hera.api.model.Block;
+import hera.api.model.BlockHash;
 import hera.api.model.BlockHeader;
 import hera.api.model.BlockchainStatus;
 import hera.client.AergoClient;
@@ -21,18 +22,18 @@ protected void blockLookup() {
         .withNonBlockingConnect()
         .build();
 
-    // lookup current blockchain status
+    // query current blockchain status
     final BlockchainStatus status = aergoClient.getBlockchainOperation().getBlockchainStatus();
 
-    // lookup block by best block hash
+    // query block by best block hash
     final Block blockByHash = aergoClient.getBlockOperation().getBlock(status.getBestBlockHash());
     System.out.println("Block by hash: " + blockByHash);
 
-    // lookup block by best height
+    // query block by best height
     final Block blockByHeight = aergoClient.getBlockOperation().getBlock(status.getBestHeight());
     System.out.println("Block by height: " + blockByHeight);
 
-    // lookup previous block by hash
+    // query previous block by hash
     final Block previousBlock =
         aergoClient.getBlockOperation().getBlock(blockByHash.getPreviousHash());
     System.out.println("Previous block: " + previousBlock);
@@ -48,18 +49,28 @@ protected void blockHeaderLookup() {
         .withNonBlockingConnect()
         .build();
 
-    // lookup best block
+    // query best block
     final BlockchainStatus status = aergoClient.getBlockchainOperation().getBlockchainStatus();
-    final Block block = aergoClient.getBlockOperation().getBlock(status.getBestBlockHash());
+    final BlockHash bestHash = status.getBestBlockHash();
+    final long bestHeight = status.getBestHeight();
 
-    // lookup 10 block headers starting from best block backward with best block hash
+    // query block header corresponding to the block hash
+    final BlockHeader blockHeaderByHash = aergoClient.getBlockOperation().getBlockHeader(bestHash);
+    System.out.println("Block header by hash: " + blockHeaderByHash);
+
+    // query block header corresponding to the block hash
+    final BlockHeader blockHeaderByHeight =
+        aergoClient.getBlockOperation().getBlockHeader(bestHeight);
+    System.out.println("Block header by height: " + blockHeaderByHeight);
+
+    // query 10 block headers starting from best block backward with best block hash
     final List<BlockHeader> blockHeadersByHash =
-        aergoClient.getBlockOperation().listBlockHeaders(block.getHash(), 10);
+        aergoClient.getBlockOperation().listBlockHeaders(bestHash, 10);
     System.out.println("Block headers by hash: " + blockHeadersByHash);
 
-    // lookup 10 block headers starting from best block backward with best block height
+    // query 10 block headers starting from best block backward with best block height
     final List<BlockHeader> blockHeadersByHeight =
-        aergoClient.getBlockOperation().listBlockHeaders(block.getBlockNumber(), 10);
+        aergoClient.getBlockOperation().listBlockHeaders(bestHeight, 10);
     System.out.println("Block headers by height: " + blockHeadersByHeight);
 
     // close the client