diff --git a/scripts/ci.sh b/scripts/ci.sh
index 0dafb8f3..3bac4304 100755
--- a/scripts/ci.sh
+++ b/scripts/ci.sh
@@ -1,52 +1,48 @@
 # This script contains commands to be executed by the CI tool.
 NPROC=$(nproc)
+GO_VERSION=1.13
+PROTOC_VERSION=3.11.1
+PROTOC_GEN_VERSION=v1.3.2
+PROTOC_GOFAST_VERSION=v1.3.1
+GRPC_VERSION=v1.24.0
 
 function version_gt() { test "$(printf '%s\n' "$@" | sort -V | head -n 1)" != "$1"; }
 
 update_go() {
-	CURRENT_GO_VERSION=`go version | sed 's/[^0-9.]*\([0-9.]*\).*/\1/'`
-	NEW_GO_VERSION=1.13
-	if version_gt $NEW_GO_VERSION $CURRENT_GO_VERSION; then	
-		echo "Update go version from $CURRENT_GO_VERSION to $NEW_GO_VERSION ..."
+	CURRENT_GO_VERSION=$(go version | sed 's/[^0-9.]*\([0-9.]*\).*/\1/')
+	if version_gt $GO_VERSION $CURRENT_GO_VERSION; then
+		echo "Update go version from $CURRENT_GO_VERSION to $GO_VERSION ..."
 		sudo rm -rf /usr/local/go
-		wget https://dl.google.com/go/go$NEW_GO_VERSION.linux-amd64.tar.gz
-		sudo mkdir /usr/local/golang/$NEW_GO_VERSION && sudo tar -C /usr/local/golang/$NEW_GO_VERSION -xzf go$NEW_GO_VERSION.linux-amd64.tar.gz
-		rm go$NEW_GO_VERSION.linux-amd64.tar.gz
+		wget https://dl.google.com/go/go$GO_VERSION.linux-amd64.tar.gz
+		sudo mkdir /usr/local/golang/$GO_VERSION && sudo tar -C /usr/local/golang/$GO_VERSION -xzf go$GO_VERSION.linux-amd64.tar.gz
+		rm go$GO_VERSION.linux-amd64.tar.gz
 
 		# remove other Go version from path
-		export PATH=`echo $PATH | sed -e 's|:/usr/local/golang/[1-9.]*/go/bin||'`
+		export PATH=$(echo $PATH | sed -e 's|:/usr/local/golang/[1-9.]*/go/bin||')
 
-		sudo ln -fs /usr/local/golang/$NEW_GO_VERSION/go/bin/go /usr/local/bin/go
+		sudo ln -fs /usr/local/golang/$GO_VERSION/go/bin/go /usr/local/bin/go
 
 		# setup GOROOT
-		export GOROOT="/usr/local/golang/$NEW_GO_VERSION/go"
+		export GOROOT="/usr/local/golang/$GO_VERSION/go"
 
 		# add new go installation to PATH
-		export PATH="$PATH:/usr/local/golang/$NEW_GO_VERSION/go/bin"
+		export PATH="$PATH:/usr/local/golang/$GO_VERSION/go/bin"
 	fi
 	go version
 }
 
 setup_protoc() {
 	echo "Setting up protoc..."
-	PROTOC_ZIP=protoc-3.10.0-linux-x86_64.zip
-	curl -0L https://github.com/google/protobuf/releases/download/v3.10.0/$PROTOC_ZIP -o $PROTOC_ZIP
+	PROTOC_ZIP=protoc-$PROTOC_VERSION-linux-x86_64.zip
+	curl -0L https://github.com/google/protobuf/releases/download/v$PROTOC_VERSION/$PROTOC_ZIP -o $PROTOC_ZIP
 	unzip -o $PROTOC_ZIP -d protoc3
 	sudo mv protoc3/bin/* /usr/local/bin/
 	sudo mv protoc3/include/* /usr/local/include/
 	rm -f PROTOC_ZIP
-	GO111MODULE=off go get -u github.com/golang/protobuf/protoc-gen-go \
-		github.com/gogo/protobuf/protoc-gen-gofast \
-		google.golang.org/grpc
-	
-	git -C $GOPATH/src/github.com/golang/protobuf/protoc-gen-go checkout v1.3.2
-	GO111MODULE=off go install github.com/golang/protobuf/protoc-gen-go
-	
-	git -C $GOPATH/src/github.com/gogo/protobuf/protoc-gen-gofast checkout v1.3.1
-	GO111MODULE=off go install github.com/gogo/protobuf/protoc-gen-gofast
 
-	git -C $GOPATH/src/google.golang.org/grpc checkout v1.24.0
-	GO111MODULE=off go install google.golang.org/grpc
+	go get -u github.com/golang/protobuf/protoc-gen-go@$PROTOC_GEN_VERSION \
+		github.com/gogo/protobuf/protoc-gen-gofast@$PROTOC_GOFAST_VERSION \
+		google.golang.org/grpc@$GRPC_VERSION
 
 	export PATH=$PATH:/usr/local/bin/protoc
 }
@@ -81,7 +77,7 @@ setup() {
 
 run_test() {
 	echo "Running tests..."
-	echo "" > coverage.txt;
+	echo "" > coverage.txt
 	for d in $(go list ./... | grep -v 'vendor\|cmd'); do
 		GOCACHE=off
 		go test -mod=vendor -v -race -tags test -coverprofile=profile.out -covermode=atomic $d