diff --git a/.travis.yml b/.travis.yml
index dd92b53df5..27e9a96cac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,6 +12,15 @@ env:
   - TEST="bash ./scripts/travis_go_checker.sh"
   - TEST="bash ./scripts/travis_rpc_checker.sh"
   - TEST="bash ./scripts/travis_rosetta_checker.sh"
+
+# upgrade docker to latest stable version
+addons:
+  apt:
+    sources:
+      - sourceline: deb https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable
+    packages:
+    - docker.io
+
 install:
   # default working directory with source code is automatically set to
   #   /home/travis/gopath/src/github.com/harmony-one/harmony
diff --git a/core/state/state_object.go b/core/state/state_object.go
index 20540371a9..8e0f3acf2b 100644
--- a/core/state/state_object.go
+++ b/core/state/state_object.go
@@ -561,7 +561,7 @@ func (s *Object) CodeSize(db Database) int {
 	if s.validatorWrapper || err != nil {
 		vcSize, errVCSize := db.ValidatorCodeSize(s.addrHash, common.BytesToHash(s.CodeHash()))
 		if errVCSize == nil && vcSize > 0 {
-			return size
+			return vcSize
 		}
 		if s.validatorWrapper {
 			s.setError(fmt.Errorf("can't load validator code size %x for account address hash %x : %v", s.CodeHash(), s.addrHash, err))
diff --git a/scripts/go_executable_build.sh b/scripts/go_executable_build.sh
index 6331aa5225..38d647fe88 100755
--- a/scripts/go_executable_build.sh
+++ b/scripts/go_executable_build.sh
@@ -26,6 +26,8 @@ fi
 DEBUG=false
 STATIC=true
 
+rm -rf .dht-127.0.0.1*
+
 unset -v progdir
 case "${0}" in
 */*) progdir="${0%/*}";;