diff --git a/.taskcluster.yml b/.taskcluster.yml
index 6b8db2a..d6b81dc 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -63,4 +63,4 @@ tasks:
         name: httpbackoff CI
         description: builds and tests httpbackoff
         owner: taskcluster-internal@mozilla.com
-        source: ${event.repository.url}
+        source: ${event.repository.url}
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 768ca27..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,32 +0,0 @@
-language: go
-
-env:
-  - GO111MODULE=on
-go:
-  - 1.15
-
-before_install:
-  - go get github.com/axw/gocov/gocov
-  - go get github.com/mattn/goveralls
-  - go get golang.org/x/tools/cmd/cover
-
-script:
-  - go test -v -coverprofile=coverage.report
-
-after_script:
-  - go tool cover -func=coverage.report
-  - ${HOME}/gopath/bin/goveralls -coverprofile=coverage.report -service=travis-ci
-
-# currently cannot customise per user fork, see:
-# https://github.com/travis-ci/travis-ci/issues/1094
-notifications:
-  irc:
-    channels:
-      - "irc.mozilla.org#taskcluster-bots"
-    on_success: change
-    on_failure: always
-    template:
-      - "%{repository}#%{build_number} (%{branch} - %{commit} : %{author}): %{message}"
-      - "Change view : %{compare_url}"
-      - "Build details : %{build_url}"
-      - "Commit message : %{commit_message}"
diff --git a/go.mod b/go.mod
index 70022f4..a179dfb 100644
--- a/go.mod
+++ b/go.mod
@@ -1,8 +1,8 @@
 module github.com/taskcluster/httpbackoff/v3
 
 require (
-	github.com/cenkalti/backoff/v3 v3.2.2
-	github.com/stretchr/testify v1.7.0
+	github.com/cenkalti/backoff/v4 v4.2.1
+	github.com/stretchr/testify v1.7.1
 )
 
 go 1.12
diff --git a/go.sum b/go.sum
index 5d638d0..b7bd020 100644
--- a/go.sum
+++ b/go.sum
@@ -1,12 +1,12 @@
-github.com/cenkalti/backoff/v3 v3.2.2 h1:cfUAAO3yvKMYKPrvhDuHSwQnhZNk/RMHKdZqKTxfm6M=
-github.com/cenkalti/backoff/v3 v3.2.2/go.mod h1:cIeZDE3IrqwwJl6VUwCN6trj1oXrTS4rc0ij+ULvLYs=
+github.com/cenkalti/backoff/v4 v4.2.1 h1:y4OZtCnogmCPw98Zjyt5a6+QwPLGkiQsYW5oUqylYbM=
+github.com/cenkalti/backoff/v4 v4.2.1/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.1 h1:5TQK59W5E3v0r2duFAb7P95B6hEeOyEnHRa8MjYSMTY=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
diff --git a/httpbackoff.go b/httpbackoff.go
index 1ce6435..3ce3a66 100644
--- a/httpbackoff.go
+++ b/httpbackoff.go
@@ -42,7 +42,7 @@ import (
 	"strconv"
 	"time"
 
-	"github.com/cenkalti/backoff/v3"
+	"github.com/cenkalti/backoff/v4"
 )
 
 var defaultClient Client = Client{
diff --git a/test_setup_test.go b/test_setup_test.go
index b9904cf..8228a31 100644
--- a/test_setup_test.go
+++ b/test_setup_test.go
@@ -9,7 +9,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/cenkalti/backoff/v3"
+	"github.com/cenkalti/backoff/v4"
 )
 
 var (
@@ -32,6 +32,9 @@ type HTTPResponse struct {
 
 // Fake auth endpoint
 func (handler *MyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if len(handler.QueuedResponses) == 0 {
+		return
+	}
 	response := handler.QueuedResponses[0]
 	handler.QueuedResponses = handler.QueuedResponses[1:]
 	w.WriteHeader(response.statusCode)