diff --git a/go.mod b/go.mod
index e54520a..2ef6f67 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,6 @@
 go 1.9
 
 require (
-	github.com/golang/protobuf v1.4.0-rc.1
-	github.com/google/go-cmp v0.3.1
+	github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208
+	github.com/google/go-cmp v0.4.0
 )
diff --git a/go.sum b/go.sum
index 6408613..3d49e1d 100644
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,11 @@
-github.com/golang/protobuf v1.4.0-rc.1 h1:axiiuL94A9bpjZyKcirx5U62av32UORcixjrwLdzvMo=
 github.com/golang/protobuf v1.4.0-rc.1/go.mod h1:ceaxUfeHdC40wWswd/P6IGgMaK3YpKi5j83Wpe3EHw8=
-github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
+github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208 h1:dwxVM2eVp+9Zdow2rAv1+ysysveVgnxKiCc/jnSsl0o=
+github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:xKAWHe0F5eneWXFV3EuXVDTCmh+JuBKY0li0aMyXATA=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
-github.com/google/go-cmp v0.3.1 h1:Xye71clBPdm5HgqGwUkwhbynsUJZhDbS20FvLhQ2izg=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
+google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
diff --git a/proto/checkinit.go b/proto/checkinit.go
index ca2124d..d7c9923 100644
--- a/proto/checkinit.go
+++ b/proto/checkinit.go
@@ -10,11 +10,6 @@
 	"google.golang.org/protobuf/runtime/protoiface"
 )
 
-// Deprecated: Use CheckInitialized instead.
-func IsInitialized(m Message) error {
-	return CheckInitialized(m)
-}
-
 // CheckInitialized returns an error if any required fields in m are not set.
 func CheckInitialized(m Message) error {
 	return checkInitialized(m.ProtoReflect())