diff --git a/.circleci/config.yml b/.circleci/config.yml
index cce45cc1..1011b5c8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -42,7 +42,7 @@ jobs:
   test:
     docker:
     # Whenever the Go version is updated here, .promu.yml should also be updated.
-    - image: circleci/golang:1.15
+    - image: circleci/golang:1.16
     # maildev containers are for running the email tests against a "real" SMTP server.
     # See notify/email_test.go for details.
     - image: djfarrelly/maildev:1.1.0
diff --git a/go.mod b/go.mod
index ea4af872..1567fc14 100644
--- a/go.mod
+++ b/go.mod
@@ -36,4 +36,4 @@ require (
 	gopkg.in/yaml.v2 v2.4.0
 )
 
-go 1.14
+go 1.16
diff --git a/scripts/genproto.sh b/scripts/genproto.sh
index ac527dbd..68676eca 100755
--- a/scripts/genproto.sh
+++ b/scripts/genproto.sh
@@ -20,6 +20,11 @@ if ! [[ $(protoc --version) =~ "3.15.8" ]]; then
 fi
 
 echo "installing plugins"
+
+# Since we run go mod download, the go.sum will change.
+# Make a backup.
+cp go.sum go.sum.bak
+
 go mod download
 
 INSTALL_PKGS="golang.org/x/tools/cmd/goimports github.com/gogo/protobuf/protoc-gen-gogofast"
@@ -46,3 +51,5 @@ for dir in ${DIRS}; do
         goimports -w *.pb.go
     popd
 done
+
+mv go.sum.bak go.sum
\ No newline at end of file
diff --git a/test/with_api_v2/acceptance/send_test.go b/test/with_api_v2/acceptance/send_test.go
index 988e2ef6..8c578f47 100644
--- a/test/with_api_v2/acceptance/send_test.go
+++ b/test/with_api_v2/acceptance/send_test.go
@@ -176,7 +176,7 @@ route:
   receiver: "default"
   group_by: [alertname]
   group_wait:      1s
-  group_interval:  1s
+  group_interval:  2s
   repeat_interval: 3s
 
 receivers: