diff --git a/proto/private/dependencies.bzl b/proto/private/dependencies.bzl
index e04d02c..d5dd5a6 100644
--- a/proto/private/dependencies.bzl
+++ b/proto/private/dependencies.bzl
@@ -21,14 +21,13 @@ dependencies = {
         ],
     },
     "com_google_protobuf": {
-        "sha256": "cc0d00955a9eb63f507b5b35367b96b75f9833602377a84ac2bc726eacac0ea1",
-        "strip_prefix": "protobuf-c132a4aa165d8ce2b65af62d4bde4a7ce08d07c3",
+        "sha256": "36bda141a127e8b8fb43f93b49efb474200ac857a9ad9a08df8aebcaba8c4543",
+        "strip_prefix": "protobuf-ee4f2492ea4e7ff120f68a792af870ee30435aa5",
         "urls": [
             # TODO(yannic): Update to release that contains fixes for
             #     `--incompatible_load_{cc,java,proto,python}_rules_from_bzl`.
-            # TODO(yannic): Update when protocolbuffers/protobuf/6391 is merged.
-            "https://mirror.bazel.build/github.com/protocolbuffers/protobuf/archive/c132a4aa165d8ce2b65af62d4bde4a7ce08d07c3.tar.gz",
-            "https://github.com/protocolbuffers/protobuf/archive/c132a4aa165d8ce2b65af62d4bde4a7ce08d07c3.tar.gz",
+            "https://mirror.bazel.build/github.com/protocolbuffers/protobuf/archive/ee4f2492ea4e7ff120f68a792af870ee30435aa5.tar.gz",
+            "https://github.com/protocolbuffers/protobuf/archive/ee4f2492ea4e7ff120f68a792af870ee30435aa5.tar.gz",
         ],
     },
     # Dependency of `com_google_protobuf`.
@@ -59,6 +58,14 @@ dependencies = {
         ],
     },
     # Dependency of `com_google_protobuf`.
+    "six": {
+        "sha256": "d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73",
+        "build_file": "@com_google_protobuf//:third_party/six.BUILD",
+        "urls": [
+            "https://pypi.python.org/packages/source/s/six/six-1.12.0.tar.gz",
+        ],
+    },
+    # Dependency of `com_google_protobuf`.
     "zlib": {
         "build_file": "@com_google_protobuf//:third_party/zlib.BUILD",
         "sha256": "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1",
diff --git a/proto/repositories.bzl b/proto/repositories.bzl
index fad5945..5d54e60 100644
--- a/proto/repositories.bzl
+++ b/proto/repositories.bzl
@@ -14,16 +14,11 @@
 
 load("//proto/private:dependencies.bzl", "dependencies")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
 
 def rules_proto_dependencies():
     for name in dependencies:
-        if name in native.existing_rules():
-            continue
-
-        http_archive(
-            name = name,
-            **dependencies[name]
-        )
+        maybe(http_archive, name, **dependencies[name])
 
 def rules_proto_toolchains():
     # Nothing to do here (yet).