diff --git a/go.mod b/go.mod
index b0e898b2007a..33f80e91cb69 100644
--- a/go.mod
+++ b/go.mod
@@ -25,7 +25,7 @@ require (
 	github.com/grpc-ecosystem/grpc-gateway v1.16.0
 	github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d
 	github.com/hdevalence/ed25519consensus v0.0.0-20210204194344-59a8610d2b87
-	github.com/improbable-eng/grpc-web v0.14.1
+	github.com/improbable-eng/grpc-web v0.15.0
 	github.com/jhump/protoreflect v1.10.1
 	github.com/lazyledger/smt v0.2.1-0.20210709230900-03ea40719554
 	github.com/magiconair/properties v1.8.5
@@ -60,6 +60,7 @@ require (
 	github.com/ChainSafe/go-schnorrkel v0.0.0-20200405005733-88cbf1b4c40d // indirect
 	github.com/Workiva/go-datastructures v1.0.52 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cenkalti/backoff/v4 v4.1.1 // indirect
 	github.com/cespare/xxhash v1.1.0 // indirect
 	github.com/cespare/xxhash/v2 v2.1.1 // indirect
 	github.com/cosmos/ledger-go v0.9.2 // indirect
diff --git a/go.sum b/go.sum
index 6699b7c8817f..797136585b6d 100644
--- a/go.sum
+++ b/go.sum
@@ -161,6 +161,8 @@ github.com/c-bata/go-prompt v0.2.2/go.mod h1:VzqtzE2ksDBcdln8G7mk2RX9QyGjH+OVqOC
 github.com/casbin/casbin/v2 v2.1.2/go.mod h1:YcPU1XXisHhLzuxH9coDNf2FbKpjGlbCg3n9yuLkIJQ=
 github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
 github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
+github.com/cenkalti/backoff/v4 v4.1.1 h1:G2HAfAmvm/GcKan2oOQpBXOd2tT2G57ZnZGWa1PxPBQ=
+github.com/cenkalti/backoff/v4 v4.1.1/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/cespare/cp v0.1.0/go.mod h1:SOGHArjBr4JWaSDEVpWpo/hNg6RoKrls6Oh40hiwW+s=
 github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
@@ -527,8 +529,8 @@ github.com/huin/goupnp v1.0.2/go.mod h1:0dxJBVBHqTMjIUMkESDTNgOOx/Mw5wYIfyFmdzSa
 github.com/huin/goutil v0.0.0-20170803182201-1ca381bf3150/go.mod h1:PpLOETDnJ0o3iZrZfqZzyLl6l7F3c6L1oWn7OICBi6o=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
-github.com/improbable-eng/grpc-web v0.14.1 h1:NrN4PY71A6tAz2sKDvC5JCauENWp0ykG8Oq1H3cpFvw=
-github.com/improbable-eng/grpc-web v0.14.1/go.mod h1:zEjGHa8DAlkoOXmswrNvhUGEYQA9UI7DhrGeHR1DMGU=
+github.com/improbable-eng/grpc-web v0.15.0 h1:BN+7z6uNXZ1tQGcNAuaU1YjsLTApzkjt2tzCixLaUPQ=
+github.com/improbable-eng/grpc-web v0.15.0/go.mod h1:1sy9HKV4Jt9aEs9JSnkWlRJPuPtwNr0l57L4f878wP8=
 github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/influxdata/flux v0.65.1/go.mod h1:J754/zds0vvpfwuq7Gc2wRdVwEodfpCFM7mYlOw2LqY=