diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5348c1d..a74d73c 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -19,7 +19,7 @@ jobs:
       linux_6_1_enabled: false
       linux_6_2_enabled: false
       linux_6_3_enabled: false
-      linux_nightly_next_enabled: true
+      linux_6_4_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
       linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
       linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
       linux_env_vars: '{"SWIFT_CERTIFICATES_ALLOW_SWIFT_CRYPTO_BETA":"1", "ENABLE_ALL_TRAITS":"1"}'
@@ -39,5 +39,4 @@ jobs:
       linux_6_1_enabled: false
       linux_6_2_enabled: false
       linux_6_3_enabled: false
-      linux_nightly_next_enabled: true
       linux_env_vars: '{"SWIFT_CERTIFICATES_ALLOW_SWIFT_CRYPTO_BETA":"1", "ENABLE_ALL_TRAITS":"1"}'
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 9307ef8..2722a70 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -10,10 +10,10 @@ on:
 jobs:
   soundness:
     name: Soundness
-    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@497d9ab8410e69981b3b2f28da24cf7bf4b8733d
+    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@0.0.15
     with:
-      api_breakage_check_container_image: "swiftlang/swift:nightly-6.4.x-noble"
-      format_check_container_image: "swiftlang/swift:nightly-6.4.x-noble"
+      api_breakage_check_container_image: "swift:6.4-resolute"
+      format_check_container_image: "swift:6.4-resolute"
       license_header_check_project_name: "Swift HTTP Server"
       linux_pre_build_command: "export SWIFT_CERTIFICATES_ALLOW_SWIFT_CRYPTO_BETA=1 ENABLE_ALL_TRAITS=1"
 
@@ -26,8 +26,7 @@ jobs:
       linux_6_1_enabled: false
       linux_6_2_enabled: false
       linux_6_3_enabled: false
-      # linux_6_3_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
-      linux_nightly_next_enabled: true
+      linux_6_4_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
       linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error"
       linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
       linux_env_vars: '{"SWIFT_CERTIFICATES_ALLOW_SWIFT_CRYPTO_BETA":"1", "ENABLE_ALL_TRAITS":"1"}'
@@ -41,7 +40,6 @@ jobs:
       linux_6_1_enabled: false
       linux_6_2_enabled: false
       linux_6_3_enabled: false
-      linux_nightly_next_enabled: true
       linux_env_vars: '{"SWIFT_CERTIFICATES_ALLOW_SWIFT_CRYPTO_BETA":"1", "ENABLE_ALL_TRAITS":"1"}'
 
   static-sdk:
@@ -59,5 +57,4 @@ jobs:
       linux_6_1_enabled: false
       linux_6_2_enabled: false
       linux_6_3_enabled: false
-      linux_nightly_next_enabled: false  # should be disabled until next is 6.4
       linux_env_vars: '{"SWIFT_CERTIFICATES_ALLOW_SWIFT_CRYPTO_BETA":"1", "ENABLE_ALL_TRAITS":"1"}'