diff --git a/Gopkg.lock b/Gopkg.lock
index 74a2f78..927932a 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -50,10 +50,9 @@
   revision = "1de0a1836ce9c3ae1bf737a0869c4f04f28a7f98"
 
 [[projects]]
-  branch = "master"
   name = "github.com/gilbertchen/go-dropbox"
   packages = ["."]
-  revision = "994e692c5061cefa14e4296600a773de7119aa15"
+  revision = "0baa9015ac2547d8b69b2e88c709aa90cfb8fbc1"
 
 [[projects]]
   name = "github.com/gilbertchen/go-ole"
@@ -99,7 +98,7 @@
 
 [[projects]]
   name = "github.com/golang/protobuf"
-  packages = ["proto","protoc-gen-go","protoc-gen-go/descriptor","protoc-gen-go/generator","protoc-gen-go/generator/internal/remap","protoc-gen-go/grpc","protoc-gen-go/plugin","ptypes","ptypes/any","ptypes/duration","ptypes/timestamp"]
+  packages = ["proto","protoc-gen-go/descriptor","ptypes","ptypes/any","ptypes/duration","ptypes/timestamp"]
   revision = "84668698ea25b64748563aa20726db66a6b8d299"
   version = "v1.3.5"
 
@@ -174,18 +173,6 @@
   packages = ["blowfish","chacha20","curve25519","ed25519","ed25519/internal/edwards25519","internal/subtle","pbkdf2","poly1305","ssh","ssh/agent","ssh/internal/bcrypt_pbkdf","ssh/terminal"]
   revision = "056763e48d71961566155f089ac0f02f1dda9b5a"
 
-[[projects]]
-  branch = "master"
-  name = "golang.org/x/exp"
-  packages = ["apidiff","cmd/apidiff"]
-  revision = "e8c3332aa8e5b8e6acb4707c3a7e5979052b20aa"
-
-[[projects]]
-  name = "golang.org/x/mod"
-  packages = ["module","semver"]
-  revision = "ed3ec21bb8e252814c380df79a80f366440ddb2d"
-  version = "v0.2.0"
-
 [[projects]]
   branch = "master"
   name = "golang.org/x/net"
@@ -209,18 +196,6 @@
   revision = "342b2e1fbaa52c93f31447ad2c6abc048c63e475"
   version = "v0.3.2"
 
-[[projects]]
-  branch = "master"
-  name = "golang.org/x/tools"
-  packages = ["cmd/goimports","go/ast/astutil","go/gcexportdata","go/internal/gcimporter","go/internal/packagesdriver","go/packages","go/types/typeutil","internal/fastwalk","internal/gocommand","internal/gopathwalk","internal/imports","internal/packagesinternal","internal/telemetry/event"]
-  revision = "700752c244080ed7ef6a61c3cfd73382cd334e57"
-
-[[projects]]
-  branch = "master"
-  name = "golang.org/x/xerrors"
-  packages = [".","internal"]
-  revision = "9bdfabe68543c54f90421aeb9a60ef8061b5b544"
-
 [[projects]]
   name = "google.golang.org/api"
   packages = ["drive/v3","googleapi","googleapi/transport","internal","internal/gensupport","internal/third_party/uritemplates","iterator","option","option/internaloption","storage/v1","transport/cert","transport/http","transport/http/internal/propagation"]
@@ -248,6 +223,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "e124cf64f7f8770e51ae52ac89030d512da946e3fdc2666ebd3a604a624dd679"
+  inputs-digest = "e462352e0b0c726247078462e30a79330ac7a8b9dc62e9ed9d1e097b684224e9"
   solver-name = "gps-cdcl"
   solver-version = 1
diff --git a/Gopkg.toml b/Gopkg.toml
index c32a597..a7e9458 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -46,8 +46,8 @@
   name = "github.com/gilbertchen/cli"
 
 [[constraint]]
-  branch = "master"
   name = "github.com/gilbertchen/go-dropbox"
+  revision = "0baa9015ac2547d8b69b2e88c709aa90cfb8fbc1"
 
 [[constraint]]
   name = "github.com/gilbertchen/go-ole"