diff --git a/.bazelrc b/.bazelrc
index f097dde..fa6c0b4 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -8,8 +8,3 @@ build --host_cxxopt=-std=c++17
 # Use Clang.
 build --action_env=CC=clang
 build --action_env=CXX=clang++
-
-# Use `WORKSPACE.bazel` instead of Bzlmod (`MODULE.bazel`).
-# TODO - migrate to Bzlmod.
-common --noenable_bzlmod
-common --enable_workspace
diff --git a/.bazelversion b/.bazelversion
index 815da58..19b860c 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-7.4.1
+6.4.0
diff --git a/.github/workflows/ci-native.yml b/.github/workflows/ci-native.yml
index 7d87df8..366a50c 100644
--- a/.github/workflows/ci-native.yml
+++ b/.github/workflows/ci-native.yml
@@ -21,7 +21,7 @@ jobs:
         os: [ubuntu-22.04, ubuntu-latest]
         # See Bazelisk README for legal values.
         # TODO - Add `latest` once it is supported. Requires using Bzlmod.
-        bazel_version: [7.x]
+        bazel_version: [6.x]
       # Don't abort other runs when one of them fails, to ease debugging.
       fail-fast: false
 
diff --git a/WORKSPACE.bazel b/WORKSPACE
similarity index 84%
rename from WORKSPACE.bazel
rename to WORKSPACE
index f7a16e6..f0e769f 100644
--- a/WORKSPACE.bazel
+++ b/WORKSPACE
@@ -40,11 +40,14 @@ load("@com_github_nelhage_rules_boost//:boost/boost.bzl", "boost_deps")
 
 boost_deps()
 
+# -- Load GRPC -----------------------------------------------------------------
+
 load("@com_google_googleapis//:repository_rules.bzl", "switched_rules_by_language")
 
 switched_rules_by_language(
     name = "com_google_googleapis_imports",
     cc = True,
+    go = True,
     grpc = True,
 )
 
@@ -56,12 +59,6 @@ load("@com_github_grpc_grpc//bazel:grpc_extra_deps.bzl", "grpc_extra_deps")
 
 grpc_extra_deps()
 
-# -- Load Rules CC -------------------------------------------------------------
-# See https://github.com/bazelbuild/rules_cc.
-load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies")
-
-rules_cc_dependencies()
-
 # -- Load Rules Foreign CC (for building Z3) -----------------------------------
 # Used for Z3.
 
@@ -75,10 +72,10 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
     name = "buildifier_prebuilt",
-    sha256 = "5dbf72e4f93917edfb91f53958d6289736adb845b2b89dbfb9bfc199a492030c",
-    strip_prefix = "buildifier-prebuilt-8.0.1",
+    sha256 = "7f85b688a4b558e2d9099340cfb510ba7179f829454fba842370bccffb67d6cc",
+    strip_prefix = "buildifier-prebuilt-7.3.1",
     urls = [
-        "http://github.com/keith/buildifier-prebuilt/archive/8.0.1.tar.gz",
+        "http://github.com/keith/buildifier-prebuilt/archive/7.3.1.tar.gz",
     ],
 )
 
diff --git a/p4_constraints/BUILD.bazel b/p4_constraints/BUILD.bazel
index 4e07c51..b430bdb 100644
--- a/p4_constraints/BUILD.bazel
+++ b/p4_constraints/BUILD.bazel
@@ -1,8 +1,4 @@
-load("@com_google_protobuf//bazel:cc_proto_library.bzl", "cc_proto_library")
-load("@rules_cc//cc:cc_library.bzl", "cc_library")
-load("@rules_cc//cc:cc_test.bzl", "cc_test")
-# GOOGLE ONLY (DO NOT REMOVE): load("//third_party/protobuf/bazel:proto_library.bzl", "proto_library")
-
+load("@com_google_googleapis_imports//:imports.bzl", "cc_proto_library")
 load("@rules_proto//proto:defs.bzl", "proto_library")
 
 package(
diff --git a/p4_constraints/backend/BUILD.bazel b/p4_constraints/backend/BUILD.bazel
index f775a7a..9d0f2aa 100644
--- a/p4_constraints/backend/BUILD.bazel
+++ b/p4_constraints/backend/BUILD.bazel
@@ -1,5 +1,3 @@
-load("@rules_cc//cc:cc_library.bzl", "cc_library")
-load("@rules_cc//cc:cc_test.bzl", "cc_test")
 load("//e2e_tests:p4check.bzl", "cmd_diff_test")
 
 package(
diff --git a/p4_constraints/cli/BUILD.bazel b/p4_constraints/cli/BUILD.bazel
index b8b6107..7c7aa4d 100644
--- a/p4_constraints/cli/BUILD.bazel
+++ b/p4_constraints/cli/BUILD.bazel
@@ -1,5 +1,3 @@
-load("@rules_cc//cc:cc_binary.bzl", "cc_binary")
-
 package(
     default_visibility = ["//visibility:public"],
     licenses = ["notice"],  # Apache 2.0
diff --git a/p4_constraints/frontend/BUILD.bazel b/p4_constraints/frontend/BUILD.bazel
index b08751e..3336fb0 100644
--- a/p4_constraints/frontend/BUILD.bazel
+++ b/p4_constraints/frontend/BUILD.bazel
@@ -1,6 +1,3 @@
-load("@rules_cc//cc:cc_library.bzl", "cc_library")
-load("@rules_cc//cc:cc_test.bzl", "cc_test")
-
 package(
     licenses = ["notice"],  # Apache 2.0
 )
diff --git a/p4_constraints_deps.bzl b/p4_constraints_deps.bzl
index f3c016c..460d70c 100644
--- a/p4_constraints_deps.bzl
+++ b/p4_constraints_deps.bzl
@@ -10,6 +10,13 @@ def p4_constraints_deps():
             urls = ["https://github.com/abseil/abseil-cpp/releases/download/20240722.0/abseil-cpp-20240722.0.tar.gz"],
             strip_prefix = "abseil-cpp-20240722.0",
         )
+    if not native.existing_rule("com_google_googleapis"):
+        http_archive(
+            name = "com_google_googleapis",
+            url = "https://github.com/googleapis/googleapis/archive/f405c718d60484124808adb7fb5963974d654bb4.zip",
+            strip_prefix = "googleapis-f405c718d60484124808adb7fb5963974d654bb4",
+            sha256 = "406b64643eede84ce3e0821a1d01f66eaf6254e79cb9c4f53be9054551935e79",
+        )
     if not native.existing_rule("com_google_gutil"):
         http_archive(
             name = "com_google_gutil",
@@ -46,15 +53,18 @@ def p4_constraints_deps():
     if not native.existing_rule("com_github_p4lang_p4runtime"):
         http_archive(
             name = "com_github_p4lang_p4runtime",
-            urls = ["https://github.com/p4lang/p4runtime/archive/970cbdc1d8663356214d33e3ba213cb91676b491.tar.gz"],
-            strip_prefix = "p4runtime-970cbdc1d8663356214d33e3ba213cb91676b491/proto",
+            # Newest commit on main as of 2025-08-27.
+            urls = ["https://github.com/p4lang/p4runtime/archive/baaf39325ceabd89b04b0d03226b6f13fc9eca29.zip"],
+            strip_prefix = "p4runtime-baaf39325ceabd89b04b0d03226b6f13fc9eca29/proto",
+            sha256 = "8b71b8a9e59c3ee7d99653e394afc44a0bfc6437dec14df619d5e1f766f129c6",
         )
     if not native.existing_rule("com_github_p4lang_p4c"):
         http_archive(
             name = "com_github_p4lang_p4c",
-            # Newest commit on main on 2021-12-07.
-            url = "https://github.com/p4lang/p4c/archive/80629201abb61d9172639fefc7bb5b9d6007db08.zip",
-            strip_prefix = "p4c-80629201abb61d9172639fefc7bb5b9d6007db08",
+            # Newest commit on main on 2024-08-01.
+            url = "https://github.com/p4lang/p4c/archive/44dbcda9c7e3d26d24baadb884b31b32d215edef.zip",
+            strip_prefix = "p4c-44dbcda9c7e3d26d24baadb884b31b32d215edef",
+            sha256 = "ae4d53d0fd41572c38b03e881a8e2d2e472df246f75d6a64555f9ff1b656b574",
         )
     if not native.existing_rule("com_github_z3prover_z3"):
         http_archive(
@@ -64,13 +74,6 @@ def p4_constraints_deps():
             sha256 = "e3aaefde68b839299cbc988178529535e66048398f7d083b40c69fe0da55f8b7",
             build_file = "@//:bazel/BUILD.z3.bazel",
         )
-    if not native.existing_rule("rules_cc"):
-        http_archive(
-            name = "rules_cc",
-            urls = ["https://github.com/bazelbuild/rules_cc/releases/download/0.0.16/rules_cc-0.0.16.tar.gz"],
-            sha256 = "bbf1ae2f83305b7053b11e4467d317a7ba3517a12cef608543c1b1c5bf48a4df",
-            strip_prefix = "rules_cc-0.0.16",
-        )
     if not native.existing_rule("rules_foreign_cc"):  # Required for Z3.
         http_archive(
             name = "rules_foreign_cc",