diff --git a/justfile b/justfile
index b45d23c..d39ea39 100644
--- a/justfile
+++ b/justfile
@@ -65,9 +65,11 @@ release new_version:
     PREV=$(grep -m1 'MARKETING_VERSION' {{pbxproj}} | sed 's/.*= *//;s/;.*//')
     echo "Releasing $PREV -> $NEW"
 
-    # 1. Bump the version in the Xcode project.
-    sed -i '' "s/MARKETING_VERSION = [^;]*/MARKETING_VERSION = $NEW/" {{pbxproj}}
-    sed -i '' "s/CURRENT_PROJECT_VERSION = [^;]*/CURRENT_PROJECT_VERSION = $NEW/" {{pbxproj}}
+    # 1. Bump the version in the Xcode project. Use a backup suffix so the -i
+    #    syntax works on both BSD sed (macOS) and GNU sed (nix dev shell).
+    sed -i.bak "s/MARKETING_VERSION = [^;]*/MARKETING_VERSION = $NEW/" {{pbxproj}}
+    sed -i.bak "s/CURRENT_PROJECT_VERSION = [^;]*/CURRENT_PROJECT_VERSION = $NEW/" {{pbxproj}}
+    rm -f {{pbxproj}}.bak
 
     # 2. Generate the changelog section for the new version from the conventional
     #    commits since the last tag, prepending it under the header.