diff --git a/.github/workflows/ciwheel.yml b/.github/workflows/ciwheel.yml
index 44dd204b18..e9df624e74 100644
--- a/.github/workflows/ciwheel.yml
+++ b/.github/workflows/ciwheel.yml
@@ -30,6 +30,7 @@ jobs:
           CIBW_BUILD: "cp3?-manylinux_x86_64"
           CIBW_SKIP: "cp35-*"
           CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014
+          arch: x86_64
           # CIBW_TEST_COMMAND: TODO
 
       - name: Build wheels macos
@@ -43,6 +44,7 @@ jobs:
           CIBW_BUILD: "cp3?-macosx_x86_64"
           CIBW_SKIP: "cp35-*"
           CIBW_ARCHS_MACOS: x86_64 universal2
+          arch: x86_64
           # CIBW_TEST_COMMAND: TODO
 
       # this action runs auditwheel automatically with the following args:
diff --git a/VERSION b/VERSION
index 53978e5317..4b9fcbec10 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.5.1-dev
+0.5.1